Academy of General Dentistry
Transcription
Academy of General Dentistry
Peer-Reviewed Journal of the Academy of General Dentistry GENERAL DENTISTRY January/February 2015 ~ Volume 63 Number 1 FORENSIC DENTISTRY n MICROBIOLOGY FIXED REMOVABLE HYBRID PROSTHESIS DIAGNOSIS AND TREATMENT PLANNING DENTAL MATERIALS n WWW.AGD.ORG Contents Departments 6Editorial Top traits 7 To the editor Outdated information? 10 Restorative Dentistry The crown to implant ratio in fixed prosthodontics 14 Endodontics Achieving and maintaining apical patency in endodontics: optimizing canal shaping procedures 80 Answers Self-Instruction exercises No. 343, 344, and 345 Clinical articles 16 Diagnosis and Treatment Planning Why the general dentist needs to know how to manage oral lichen planus Stephanie M. Price, DDS Valerie A. Murrah, DMD, MS SELF -INSTRUCTION Continuing Dental Education (CDE) Opportunities Earn 2 hours of CDE credit by signing up for and completing the SELF-INSTRUCTION exercises based on various subjects. 23 Microbiology Investigation of antibacterial efficacy of Acacia nilotica against salivary mutans streptococci: a randomized control trial Devanand Gupta, BDS, MDS Rajendra Kumar Gupta, PhD 28 Self-Instruction Exercise No. 361 Roger A. Solow, DDS Please visit www.agd.org/ gdindex to peruse our Index of Articles. Arranged by topic, this index provides a comprehensive list of articles published on a particular topic in past issues and includes PubMed citation information. 48 Anesthesia and Pain Control Local anesthetic calculations: avoiding trouble with pediatric patients Mana Saraghi, DMD Paul A. Moore, DMD, PhD, MPH Elliot V. Hersh, DMD, MS, PhD 53 Self-Instruction Exercise No. 362 54 Forensic Dentistry The role of the dentist in identifying missing and unidentified persons Amber D. Riley, RDH, MS 30 Diagnosis and Treatment Planning Clinical considerations for selecting implant abutments for fixed prosthodontics General Dentistry Index of Articles available online. SELF -INSTRUCTION 37 Dental Materials Surgical repair of invasive cervical root resorption with calcium enriched mixture cement: a case report Saeed Asgary, DDS, MS Mahta Fazlyab, DDS, MS 41 Office Design Evaluation of 3 dental unit waterline contamination testing methods Nuala Porteous, BDS, MPH Yuyu Sun, PhD John Schoolfield, MS 58 Non-Surgical Endodontics Nonsurgical endodontic treatment of permanent maxillary incisors with immature apex and a large periapical lesion: a case report Gautam P. Badole, MDS M.M. Warhadpande, MDS Rakesh N. Bahadure, MDS Shital G. Badole, BDS SELF -INSTRUCTION 61 Fixed Removable Hybrid Prosthesis Stress analysis of mandibular implant-retained overdenture with independent attachment system: effect of restoration space and attachment height Behnaz Ebadian, DDS, MSc Saeid Talebi, MSc Niloufar Khodaeian, DDS, MSc Mahmoud Farzin, PhD 68 Self-Instruction Exercise No. 363 www.agd.org General Dentistry January/February 2015 1 69 Oral Medicine, Oral Diagnosis, Oral Pathology p53 expression in oral lichenoid lesions and oral lichen planus A. Arreaza, MSc H. Rivera, MSc M. Correnti, PhD 73 Dental Materials Effect of imaging powders on the bond strength of resin cement Christopher R. Jordan, DMD, MS Clifton W. Bailey, DDS Deborah L. Ashcraft-Olmscheid, DMD, MS Kraig S. Vandewalle, DDS, MS 78 Implant Maintenance Crestal approach for removing a migrated dental implant from the maxillary sinus: a case report Raid Sadda, DDS, MS, MFDRCSI e1 Cancer Screening Ameloblastic carcinoma of the mandible manifesting as an infected odontogenic cyst Adepitan A. Owosho, BChD Anitha Potluri, DMD Richard E. Bauer III, DMD, MD Elizabeth A. Bilodeau, DMD, MD, MSEd e5 Surgical Orthodontics A large dentigerous cyst treated with decompression and orthosurgical traction: a case report Rodrigo Dias Nascimento, PhD Fernando Vagner Raldi, PhD Michelle Bianchi de Moraes, PhD Paula Elaine Cardoso, PhD Deborah Holleben, DDS Instructions for Authors For information on submitting a manuscript for publication in General Dentistry, please visit www.agd.org/gdauthorinfo. 2 January/February 2015 General Dentistry www.agd.org e9 Dental Materials Impact of toothbrushing with a dentifrice containing calcium peroxide on enamel color and roughness Diala Aretha de Sousa Feitosa, DDS, MSc Boniek Castillo Dutra Borges, PhD Fabio Henrique de Sa Leitao Pinheiro, PhD Rosangela Marques Duarte, PhD Renato Evangelista de Araujo, PhD Rodivan Braz, PhD Maria do Carmo Moreira da Silva Santos, PhD Marcos Antonio Japiassu Resende Montes, PhD e12 Obturation Techniques Apical plug technique in a calcified immature tooth: a case report Kumar Raghav Gujjar, MDS Ratika Sharma, MDS Amith H. V., MDS Smitha Amith, MDS Indushekar K. R., MDS e16 Diagnosis and Treatment Planning Central giant cell lesion: diagnosis to rehabilitation Ana Carolina Amorim Pellicioli, DDS Thieni Kaefer, DDS Marco Antonio Trevizani Martins, DDS, PhD Vinicius Coelho Carrard, DDS, PhD Manoela Domingues Martins, DDS, PhD e20 Diagnosis and Treatment Planning Alveolar ridge splitting for implant placement: a review of the procedure and report of 3 cases Prakash S. Talreja, MDS Chandrashekhar R. Suvarna, BDS Preeti P. Talreja, MDS Advisory Board For Advisory Board members’ biographies, visit www.agd.org/ gdadvisoryboard. Dental Materials Howard S. Glazer, DDS, FAGD e24 Prosthodontics/Removable Management of severe mandibular deviation following partial mandibular resection: a case report e32 Diagnosis and Treatment Planning Atypical presentation of salivary mucocele: diagnosis and management Husain Harianawala, BDS, MDS Mohit Kheur, BDS, MDS Supriya Kheur, BDS, MDS Jay Matani, BDS, MDS Kumar Nilesh, MDS Jagadish Chandra, MDS Dental Public Health Larry Williams, DDS, ABGD, MAGD Esthetic Dentistry Wynn H. Okuda, DMD Endodontics Gerald N. Glickman, MS, DDS, MBA, JD e28 Diagnosis of Oral Pathology Rare oral cartilaginous choristoma: a case report and review of the literature Marina Lara de Carli, DDS, PhD Felipe Fornias Sperandio, DDS, PhD Fernanda Rafaelly de Oliveira Pedreira, DDS Alessandro Antonio Costa Pereira, DDS, PhD Joao Adolfo Costa Hanemann, DDS, PhD Geriatric Dentistry Eric Zane Shapira, DDS, MAGD, MA, MHAv Implantology Wesley Blakeslee, DMD, FAGD Oral and Maxillofacial Pathology John Svirsky, DDS, MEd Oral and Maxillofacial Radiology Dale A. Miles, BA, DDS, MS, FRCD(C) Coming next issue In the March/April issue of General Dentistry • Comparison of the effectiveness of Endo-eze, Navitip, and Navitip FX irrigation devices in the cleansing of root canal walls instrumented with oscillatory and rotary techniques • Surface characteristics of resin composite materials after finishing and polishing • The effect of specially designed and managed occlusal devices on patient symptoms and pain: a cohort study Oral and Maxillofacial Surgery Karl Koerner, DDS, FAGD Orthodontics Yosh Jefferson, DMD, FAGD Pain Management Henry A. Gremillion, DDS, MAGD Pediatrics Jane Soxman, DDS Periodontics Samuel B. Low, DDS, MS, MEd Pharmacology Thomas Viola, RPh, CCP Practice Management Mert N. Aksu, DDS, JD, MHSA, FAGD Prosthodontics Joseph Massad, DDS Jack Piermatti, DMD 4 January/February 2015 General Dentistry www.agd.org In the February issue of AGD Impact • Career transitions for dental students and new dentists • Treating bruxism General Dentistry 560 W. Lake St., Sixth Floor Chicago, IL 60661-6600 General Dentistry (ISSN 0363-6771) is published bimonthly in 2015 by the AGD, 560 W. Lake St., Sixth Floor, Chicago, IL 60661-6600. AGD members receive General Dentistry as part of membership. 888.AGD.DENT (888.243.3368) www.agd.org Email: [email protected] Fax: 312.335.3442 Back Issues and Change of Address Members, call 888.AGD.DENT (888.243.3368) and ask for a Member Services representative. Nonmembers, call Derria Murphy (ext. 4097). Mailing Lists For information about ordering AGD mailing lists, call Derria Murphy (ext. 4097). All materials subject to copying and appearing in General Dentistry may be photocopied for the noncommercial purposes of scientific or educational advancement. Reproduction of any portion of General Dentistry for commercial purposes is strictly prohibited unless the publisher’s written permission is obtained. Disclaimer The AGD does not necessarily endorse opinions or statements contained in essays or editorials published in General Dentistry. The publication of advertisements in General Dentistry does not indicate endorsement for products and services. AGD approval for continuing education courses or course sponsors will be clearly stated. Periodicals postage paid at Chicago, IL and additional mailing office. POSTMASTER: Send address changes to General Dentistry, 560 W. Lake St., Sixth Floor, Chicago, IL 60661-6600. Email: [email protected]. Canadian mailing information: IPM Agreement number 40047941. Change of address or undeliverable copies should be sent to: Station A, P.O. Box 54, Windsor, Ontario, N9A 6J5, Canada. Email: [email protected]. The nonmember individual subscription rate for General Dentistry is $100 for the print version, $100 for the online version, and $175 for print and online versions; the nonmember institution rate is $300 (add $20 for Canada and $50 for outside the U.S. and Canada). Single copies of General Dentistry are available to nonmember individuals for $15 and nonmember institutions for $18 (add $3 for orders outside the U.S.). © Copyright 2015 by the Academy of General Dentistry. All rights reserved. Associate Editor Eric K. Curtis, DDS, MAGD Director, Communications Cathy McNamara Fitzgerald Managing Editor Tiffany Nicole Slade Acquisitions Editor Rebecca Palmer Associate Editor, Publications Sheila Stevens Saldeen Manager, Production/Design Timothy J. Henney Associate Designer Jason Thomas Graphic Designer Phillip Montwill Advertising M.J. Mrvica Associates 2 West Taunton Ave. Berlin, NJ 08009 856.768.9360 [email protected] Reprints Rhonda Brown Foster Printing Company 866.879.9144, ext. 194 Fax: 219.561.2017 [email protected] Subscriptions Derria Murphy Academy of General Dentistry 888.AGD.DENT (888.243.3368), ext. 4097 [email protected] Your voice for excellence through education and advocacy AGD Lead Corporate Sponsor Editor Roger D. Winland, DDS, MS, MAGD AGD Corporate Sponsors www.agd.org General Dentistry January/February 2015 5 Editorial Top traits A s a dentist, you studied hard in dental school, and you now continue learning through advanced certification and CE classes, as well as by reading articles in General Dentistry. You are a seasoned and trusted dentist at the top of your profession with years of experience. But how will you stay there? Perhaps the following traits— which I have observed in dentists I respect—will help guide you as you navigate the coming years. new things, ultimately figuring out what works best for your patients. An anonymous sage once said, “Getting something done is an accomplishment; getting something done right is an achievement.” Modesty Positive attitude Great dentists maintain a positive attitude and avoid slipping into negativity. Maintaining a positive outlook, even when confronted with difficult situations, is a start on the road to success. A negative outlook will severely diminish your opportunities. Tenacity Tenacity is a trait worth developing. Little is ever accomplished with just one letter, e-mail, telephone call, request, or CE course. There is a slogan in the safety industry that “Triumph is just an umph added to try.”1 In my experience, the most successful dentists embody a tenacious spirit. They are undaunted by adversity and frequently persist with their goals long after others might have given up. It is this trait that tends to propel practitioners into professional successes. Honesty Always practice honesty in your practice, as carelessness with facts can destroy your credibility. Some patients present at our practices after having experienced dishonesty with medical or dental providers. Many have found that promises made by so-called professionals did not live up to their expectations. To avoid disappointing your patients, always carefully discuss with them their diagnoses and all available treatment options, including the costs and possible outcomes of each treatment. Dentists who run honest practices tend to have happier patients. Happy patients return for many years, which is always the objective in running a successful practice. Innovation Patients like to sense that their dentist is breaking ground with new technology that they have personally researched or possibly originated. Are you the type of dentist who is stuck in old ways of doing things? Do you refuse to explore new technology, even when it has proven successful? Successful dentists have a way of finding new ways of doing things even as they continue to maximize proven techniques. Be open to trying 6 January/February 2015 General Dentistry www.agd.org Another good trait to develop is professional modesty. It is more rewarding to have your patients and staff recognize your abilities than to point them out yourself. While psychologists have longconsidered self-esteem an essential element of a healthy personality, this is not achieved by self-promotion.2 Train your staff to take pride in their work and in every successful outcome and interaction with patients, but be careful not to constantly pat yourselves on the back about a job well done. Doing so may detract from the cultivation of new skills and potentially lead to missteps. Traits of successful dentists include both professional excellence and a healthy dose of modesty—even when everything is going well. Style Your style is not about your clothes, but about who you are as a dentist in your clothes. Whether you are an introvert or an extravert by nature, try to develop a loving, caring, professional style to complement your interactions with your staff and patients. Loyalty Develop downward loyalty. Great dentists protect their staff and provide the training and attention needed to develop a good rapport. Along the way, your staff will appreciate your straightforwardness and support that is simple and direct. A cohesive staff is bound by this loyalty, and the power of this trait is evident to all who enter your practice. Will Rogers once said that “The road to success is dotted with many tempting parking places.” As you move forward in your experience as a dentist, you will inevitably be met with challenges. However, continuously adapting the traits mentioned above will help secure your success for many years to come. Roger D. Winland, DDS, MS, MAGD Editor References 1. SAFTENG.net. Safety Slogans. Available at: http://www.safteng.net/index.php?option= com_content&view=article&id=2702&Itemid=178. Accessed November 13, 2014. 2. About Education. What is Self-Esteem? Available at: http://psychology.about.com/od/ sindex/f/what-is-self-esteem.htm. Accessed November 13, 2014. To the editor Outdated information? I have just completed reading the November/December 2014 issue of General Dentistry, which I look forward to every month as a benefit of my AGD membership over the last 10 years. Unfortunately, you have chosen to publish an article (“Perspective of cardiologists on the continuation or discontinuation of antiplatelet therapy before dental treatment: a questionnaire-based study,” pp. 64-68) with so many egregious fallacies and outdated information, that under advisement from the Editor, Dr. Roger Winland, I have put the proverbial pen to paper. For full disclosure, I have been a licensed pharmacist for 24 years and hold a specialty in dental pharmacology. I am a reviewer for a number of peer-reviewed journals (including General Dentistry), am on the Editorial Board for the Journal of the American Dental Association, and have numerous publications in the peer reviewed literature including book chapters. I teach, perform original research, and am on faculty at 2 universities which include the Oregon Health & Sciences University in Portland, where I am the only non-dentist in the Faculty of Dentistry. While I typically applaud original research, this article is far below the standards of General Dentistry and the conclusions reported may not be in support of the current standard of care or published guidelines and could in fact result in patient harm. I cannot believe that through the usually rigorous editorial process, this manuscript was allowed to make it to print, and from the outset, I may even suggest that the Editor consider a possible retraction. I have included just a few of my comments in the highlighted sections of the attached document. I will try to be succinct in my concerns. References This article has 49 references of which 42 are over 5 years old. Four of the remaining 7 references refer to website addresses on the internet, 1 reference (No. 9) cites an entire textbook (Sweetman SC, ed. Martindale: The Complete Drug Reference. 34th ed. London: Pharmaceutical Press; 2013), and the remaining 2 articles were published in 2009 and are based on 2008 data (again more than 5 years old). Many of the citations refer to articles published in journals which are not listed in the Index Medicus (such as The Journal of Indian Society of Periodontology). Abstract The abstract does NOT accurately reflect the title and, therefore, purpose of the article, which immediately gave me pause. “Perspective of cardiologists on the continuation or discontinuation of antiplatelet therapy before dental treatment: a questionnairebased study” is very different than what the Abstract reports as, “a survey of 50 cardiologists was conducted regarding suggested guidelines for dentists in the management of patients who are taking anticoagulant medication.” Antiplatelet medications and anticoagulant medications are NOT the same drug class. This type of disinformation will do nothing to add clarity to the already confusing topic of medically complex patients and their management in the dental realm. I cannot emphasize enough that the rest of the article continues the theme of using these terms interchangeably and worse, makes recommendations on how to manage these patients based on VERY OUTDATED information—something that I see as a patient safety issue. Main article The authors miss an important opportunity to clearly define the issue and offer a review of the recent literature in order to help guide modern dental practice. The 4 drugs mentioned in the very first paragraph (aspirin, clopidogrel, dipyridamole, and warfarin) comprise an incomplete and outdated list of both anticoagulant and antiplatelet medications, but nowhere in this article is any reference made to the more common and currently used medications: prasugrel and ticagrelor (antiplatelet agents) and rivaroxaban, dabigatran, apixaban, vorapaxar, and edoxaban (anticoagulant agents). Many recommendations are cited, such as the American College of Chest Physicians in 2006, even though this does not appear as a referenced citation, and this 2006 reference does NOT represent the most recent guidelines supported by the American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. These types of statements are rampant throughout the text and in almost every case refer to outdated information: “…with increasing concern over the thromboembolic risk, this is no longer recommended.7 ” (Jaya Kumar A, Kumari MM, Arora N, Haritha A. Is anti-platelet therapy interruption a real clinical issue? Its implications in dentistry and particularly in periodontics. J Ind Soc Periodontol. 2009;13(3):121-125.) To further add to the confusion and misinformation, the middle section on monitoring and blood tests has very little to do with antiplatelet therapy (on which this study focused), and everything to with anticoagulant treatment. It is therefore possible that oral healthcare professionals, based on this article, will begin to use INR measurements to gauge a patients’ antiplatelet capacity which is NOT recommended. Furthermore, statements such as, “An INR is advised for all patients on warfarin or heparin therapy,31” are entirely incorrect, misleading, and NOT even supported by the reference that is cited (No. 31). INR is not a measurement of heparin efficacy and SHOULD NOT be ordered. The appropriate test is a PTT. The article also states that, “before dental therapy, patients with antiplatelet regimens should have bleeding time, clotting time, ECG, routine investigations, blood sugar level, and blood pressure tests.” This is definitely not the type of information we should encourage general practitioners to follow. My intention is certainly not to rewrite this manuscript nor point out every error of fact, but I will close with just a few additional conclusions the authors suggest: • “If a patient is on a dual therapy of aspirin and clopidogrel, it is recommended that the dental procedure be performed in a hospital setting.” www.agd.org General Dentistry January/February 2015 7 • “Thomason et al reported severe bleeding following a gingivectomy in a patient taking 150 mg aspirin qd, which was resolved by platelet transfusion.27” This was a single case published in 1999. • “Shalom & Wong concluded that cutaneous bleeding tests should not be used to estimate the hemorrhagic risk in patients on anticoagulant therapy.36 ” This was not their conclusion and this study in plastic surgery cases from 2003 looked at aspirin (an antiplatelet agent, NOT an anticoagulant). • “Oral surgical procedures must be done at the beginning of the day, as it allows more time to deal with any bleeding episode.41 ” Reference is from 2002. • “Patients with the following medical problems taking antiplatelet medications should not be treated in primary care without medical advice or should be referred to a hospitalbased dental clinic: liver impairment and/or alcoholism; renal failure; hemostasis disorders; and patients currently receiving cytotoxic medication or dual antiplatelet therapy.” • “Medical consent is mandatory in cardiac patients taking antiplatelet therapy.” These few statements alone, if followed, may limit many of our medically complex patients with oral pathologies from getting the oral healthcare they require. My phone has not stopped ringing with concerned dental colleagues and AGD members who are confused by this recent publication. I look forward to hearing from you on this matter. Mark Donaldson, BSP, RPH, PHARMD, FASHP, FACHE Kalispell, Montana (with enclosures) Response from Dr. Singh et al At the outset, we must congratulate your journal for having such an enlightened and knowledgeable readership. We appreciate the points raised by our pharmacist friend as we genuinely believe that healthy criticism is a sure shot way forward towards academic growth. In fact, our rigorous preparation to answer the various queries raised by the reader has improved our understanding of the subject manifold. We would like to thank you for sharing the concerns of the reader and for providing us with an opportunity to respond to each one of them. Antiplatelet and anticoagulant medications We agree with the reader’s view that antiplatelet and anticoagulant medications are NOT the same drug class. In our questionnaire, the questions were targeted at antiplatelet agents only. However, the responses given by the cardiologists were not regarding patients on antiplatelet therapy alone. They pointed toward a growing number of patients on combined antiplatelet and anticoagulant therapy. INR has been added when cardiologists mentioned its use in patients under anticoagulant therapy. To maintain the transparency and authenticity of the survey, we mentioned both the terms in our Discussion. In fact, our Abstract begins with these terms. However, a typographical error in the last line of the Abstract fails to mention antiplatelet medication also. [Editor’s note: the typographical error was made 8 January/February 2015 General Dentistry www.agd.org by the authors]. We deeply regret this error. The title does not mention the term anticoagulant therapy, as our survey focused on antiplatelet therapy, as reflected by our questionnaire. Incomplete and outdated information The reader claims that we provided an incomplete and outdated list of antiplatelet and anticoagulant medications with no mention of more common and currently used medications. We must EMPHASIZE that the drugs mentioned by us were based on the responses of practicing cardiologists regarding drugs most frequently used in Indore, India. No leading questions were put forth, and no bias was incorporated by the authors. Standard of care varies temporally and geographically We have focused on drugs most frequently used in our geographic location. The newer drugs mentioned by our esteemed reader were not frequently used in Indore, India at the time of submission of our article. After receiving the letter from our reader, we extensively researched these drugs and found that many of them are highly potent medications. However, we feel that discussion about the merits of usage of newer drugs and their protocols is beyond the scope of our article. Why was INR mentioned in a study focusing on antiplatelet therapy? As mentioned earlier, the surveyed cardiologists mentioned the practice of checking INR when a patient is on anticoagulants. We have clearly stated that it is a test of coagulation. Earlier in the same paragraph, we mentioned that there is no suitable test to assess the increased risk of bleeding in patients taking antiplatelet therapy; platelet function is normally assessed using the cutaneous bleeding time test. Only an ignorant oral health care professional will start using INR to gauge antiplatelet capacity The reader claims that we are recommending bleeding time, clotting time, ECG, routine investigations, blood sugar level, and blood pressure tests in all patients on antiplatelet regimen before dental therapy. This however is MISCONSTRUED, as we were merely reporting the opinions of surveyed cardiologists when asked for medical consent. The reader has pointed out that many “conclusions” attributed to us or cited by us are outdated and would limit many medically complex patients with oral pathologies from getting requisite oral health care. This could not be further from the truth as we strongly believe in the idiom, “Discretion is the better part of valor.” Nowhere in the article have we recommended not to provide care to the patient, but have only advised caution and necessary preparedness for any untoward eventuality (however rare) that can happen in a surgical procedure. The reader claims that dentists might be alarmed and therefore refuse cases requiring treatment. This is a dangerous fallacy. By this account, “Ignorance is bliss.” There seems to be a difference of perception between the authors and the reader owing to the difference in healthcare standards and facilities in the developing and developed world. Average dental clinics in India are probably not as equipped to handle emergencies as those in the Western world. Hence, we would always lean towards caution as opposed to blind overconfidence. Medical consent and physician referral The reader has objected to our statement regarding medical consent being mandatory for cardiac patients on antiplatelet therapy. We steadfastly stand by our opinion based on our clinical experience that the medical referral should be mandatory for cardiac patients on antiplatelet medication. Dental practitioners lack the clinical acumen of judging cardiac status of patients. Our opinion is substantiated in a 2012 article by Can et al, who reported only 30% of the surveyed dentists had knowledge about the consequence of interrupting treatment with clopidogrel, and only 30% were aware of the high mortality rates associated with stent thrombosis.1 All of the respondents were cautious and expressed willingness to consult a cardiologist before interrupting aspirin and/or clopidogrel. None of the respondents knew the names of new generation antiplatelet agents such as prasugrel or ticagrelor. More importantly, the educational awareness and level of understanding of the patients in our geographic area mandate extra precautions to prevent any untoward sequelae and medicolegal complications. Many times, patients are noncompliant with their regimens. We are not depriving patients of dental care as claimed by our esteemed reader; rather, we are making their dental management safer. References The reader points out that most of the references cited by us are old and outdated. We would like to share a few facts: • While this article is based on a study conducted nearly 3 years ago, the article itself was in the process of publication for almost 1.5 years. • Most of the drugs mentioned by our respondents have been used for a long period of time. Hence, their references are not as recent as those of the drugs mentioned by our reader. • Forty of the 49 references cited by us are of the current century, hence they are not archaic as claimed. • Old data need not need be written off. In fact, we have seen (as in the case of focal infection theory) old theories being rejuvenated on account of newer understanding. Hence we should not demean what is old, but look at it in a better light. • Many times, adverse events are not reported in the literature. Therefore, case report references which have done so need to be given meritorious consideration. As the idiom states, “One swallow does not a summer make.” • The Journal of Indian Society of Periodontology may not be listed in the Index Medicus. However, it is listed in many other indices, most notably PubMed. • Standard textbooks and credible websites are an important source of information and knowledge for clinicians. Not all general dental practitioners read journals or articles. The nuances of web research are mostly developed at the postgraduate level. Clarifications and addendum • Some respondents mentioned INR as an investigation when the patient was on anticoagulant therapy. To avoid the confusion in the minds of readers, we have clearly mentioned that INR and partial thromboplastin time have been used to evaluate anticoagulant levels. • Due to a typographical error, lines cited to reference No. 34 have erroneously mentioned ‘antiplatelet’ instead of ‘anticoagulant.’ [Editor’s note: the typographical error was made by the authors.] We would also like to clarify that a PTT is a test to evaluate anticoagulant status in patients on heparin, and INR is to be considered in patients on warfarin. • In lines cited to reference No. 36, cutaneous bleeding tests should not be used to estimate the hemorrhagic risk in patients on antiplatelet therapy. It has been erroneously mentioned as anticoagulant therapy. Concluding remarks We had no intention to confuse or alarm general dental practitioners but only to sensitize them to a controversial topic. Each specialist or person looks at the same situation from a different perspective. Wisdom lies in accepting these differences in perception and cultural traits with an open mind. The knowledge domains of a dental surgeon, a cardiologist, and an eminent pharmacist shall be very different, and we have no qualms in admitting that a pharmacist will have a final word on drugs and their merits. In the same vein, we would humbly like to profess that prescribing a drug is a physician’s prerogative, and dental management of patients as well as seeking physician referral and medical consent comes under the jurisdiction of dental surgeons. We hope we have been able to clarify our position and satisfactorily answer the queries raised by our esteemed reader. We wholeheartedly appreciate the concern and efforts on the part of our reader. We look forward to any further correspondence in this matter, if required. Reference Can MM, Biteker M, Babur G, Ozveren O, Serebruany VL. Knowledge, attitude and perception of antiplatelet therapy among dentists in Central Eastern Turkey. World J Cardiol. 2012; 4(7):226-230. General Dentistry welcomes correspondence from its readers. You can send letters to General Dentistry Editor, AGD, 560 W. Lake St., 6th Floor, Chicago, IL 60661-6600, or email us at [email protected]. The editors reserve the right to edit all submissions. We cannot print letters that have been submitted to other publications. www.agd.org General Dentistry January/February 2015 9 Restorative Dentistry The crown to implant ratio in fixed prosthodontics Roger A. Solow, DDS P rior to the advent of osseointegrated implants, a periodontal prosthesis was the preferred treatment for a patient with significant periodontal bone loss and altered crown to root ratios (C/Rs). The C/R is the radiographic amount of tooth out of alveolar bone compared to the amount within alveolar bone.1 These patients have missing, mobile, or malposed teeth with open gingival embrasures that pose functional and esthetic problems. Drifted, over-erupted, and flared teeth are repositioned and then restored with fixed partial prostheses. Splinting the remaining teeth and creating a therapeutic occlusion improves force distribution and preserves the compromised teeth.2 This type of restoration and occlusal adjustment can be used to decrease mobility in teeth with attachment loss. Additionally, implant-supported restorations can predictably replace lost teeth or teeth with a hopeless prognosis. A dentist may encounter a normal, reduced, or amplified restorative space when treating these areas; such changes result in altered crown to implant ratios (C/Is). The C/I is the radiographic amount of the crown-abutment-implant complex out of alveolar bone compared to the amount within alveolar bone.3 Altered C/R and C/I are not equivalent; this is important to understand when treatment planning for implant-supported restorations. Teeth undergo a 2-phase displacement on loading as the periodontal ligament (PDL) is initially compressed prior to engaging the alveolar bone.4 The PDL creates stress distribution along the root length as well as a protective neuromuscular response. In contrast, implants when loaded undergo a 1-phase linear deformation with stress concentrated at the bone crest without a protective response. The C/I affects the periodontium for all implant designs: 1-piece implant with a pre-established restorative margin, 2-piece implant with the implant shoulder as the restorative margin, or bone-level implant with the restorative margin on the abutment. This column reviews the clinical considerations of C/I in fixed prosthodontics. A normal C/I is similar to the C/R for natural teeth (Fig. 1). The C/R of maxillary and mandibular first premolars have been measured at 0.57 and 0.61, respectively, and for maxillary and mandibular first molars at 0.63 and 0.54, respectively.5 A 13 mm length tissue-level implant with a typical size crown would approximate a normal C/R. Although the intent of implant restoration is to achieve a biomimetic replacement of lost structure, there is no reason to use the root length as the implant length, since width is more important than length to minimize crestal cortical bone stress.6-8 The occlusal design for posterior teeth implant-supported restorations is similar to natural teeth and should allow only vertical force during closure or chewing excursions.9,10 Contact on closure should be centered over the implant to maintain vertical force and minimize shear stress. In mixed tooth and implant restorations, implants should not contact at the same time or heavier than teeth on firm closure. The PDL creates an intrusion displacement 10 January/February 2015 General Dentistry on teeth that the implants don’t have. The posterior occlusion should be refined so that implants receive a delayed initial contact and a lighter final contact than teeth.11 Implant canine guidance avoids the increased stress to prosthetic components and supporting bone from group function excursive contacts.12 To prevent force overload at the buccal crestal bone, it is crucial that anterior implant-supported restorations do not contact heavier than adjacent teeth during closure. Any loss of bone may create gingival recession with abutment exposure or asymmetric levels of the gingival margins. This region typically has minimal bone thickness and is often augmented prior to or at implant placement. The dentist should place a gloved fingernail on the facial surface of the crown to detect heavy contact on firm or light closure. Lateral and protrusive excursion contacts should be on the strongest anterior tooth or implant to separate the posterior teeth. In cases of anticipated excess force, such as patients with a history of bruxism and attrition, multiple anterior teeth can contact in concert during the excursion to distribute the force over a greater surface area. A reduced C/I typically occurs when there is minimal interocclusal space due to over-eruption of the opposing tooth, or severe attrition with compensatory eruption of many teeth (Fig. 2 and 3). Most posterior teeth have a crown height of 7.08.5 mm.5 A reduced restorative space could be defined as <5 mm, where the dentist does not have a choice to use either cement or screw retention but is restricted to using screw retention. Cemented restorations need 5 mm space, consisting of 2 mm for material and 3 mm for minimal abutment height to resist dislodgement. Treatment planning for a reduced C/I involves evaluating the esthetics and functional occlusion to determine the patient’s most appropriate procedure. Alternatives include occlusal adjustment of the opposing tooth, restoration of the opposing tooth Fig. 1. Normal crown to implant ratio (C/I). The gold crown was placed at the gingival margin similar to the adjacent gold crowns on natural teeth. www.agd.org Fig. 2. Reduced C/I indicating the need for a screw-retained crown. The distance from the implant platform to the opposing tooth is 4 mm. Fig. 3. Screw-retained gold crown with intracrevicular margins for predictable cement clearance. Note the crown height compared to the adjacent tooth. Fig. 4. Tissue-level implant placed subcrestal near the adjacent tooth apex. The surgeon achieved bicortical engagement and stability but compromised vertical position. Fig. 5. Ten-year soft tissue reaction to excellent patient hygiene. The distal papilla of tooth No. 5 was lost due to the absence of bone on the mesial of tooth No. 4. with occlusal reduction to compensate for the over-eruption, orthodontic intrusion with temporary anchorage devices, and segmented osteotomy with repositioning. The restorative dentist always needs 2 measurements from the surgeon for the implant restoration treatment plan: sulcus depth and restorative space. Sulcus depth (gingival margin to implant shoulder) determines the abutment collar dimension. Restorative space (gingival margin to the opposing cusp) determines whether a screw-retained crown or an abutment with cemented crown are indicated. The surgeon can use a periodontal probe and communicate these measurements at the implant integration verification appointment. The restorative dentist can then plan for a screw-retained crown with provisional abutment or order the appropriate definitive abutment, precluding the need to maintain a large inventory of prosthetic components. An amplified C/I may result from lost bone from periodontal destruction or trauma, failed osseous grafting, or submerged implant placement. The surgeon should place the implant to avoid problems in the vertical axis that compromise oral hygiene and papilla support (Fig. 4 and 5). However, deep placement may be needed to engage bone, or reducing gingival height may create an esthetic problem. A deep implant platform requires a stock mesostructure or a custom abutment to avoid a restoration margin >1 mm subgingival with unpredictable cement clearance. Alternatively, a screw-retained crown can be used. A titanium stock mesostructure or titanium custom abutment would provide better soft tissue adhesion than porcelain or gold.13 C/I problems also occur in concert with porous posterior bone and increased forces on molar sites. This is especially true with maxillary sinus grafting cases, where pneumatized sinuses and minimal native bone further challenge the dentist to manage occlusal force (Fig. 6 and 7). The increased height of restorative material above the implant platform creates a vertical cantilever that magnifies torque stresses on the crestal bone from lateral loading. Also, the lost posterior bone resorbs preferentially from the buccal side, creating a horizontal cantilever in the restoration. It is critical to remove all excursive interferences so force is aligned with the long axis of the implant. The increased restorative space and a short implant (<10 mm), dictated by a limited amount of available bone, synergistically increase the C/I. Amplified C/I >2.0 are well-tolerated and again show how implant-supported restorations differ www.agd.org General Dentistry January/February 2015 11 Fig. 6. Multiple parallel implants with stock abutment at site No. 11 and custom abutments at sites No. 12-14. Note the amplified restorative space of the posterior implants. from natural teeth with compromised bone support in the periodontal prosthesis paradigm. Short implants may allow implant placement in nongrafted atrophic ridges and avoid invasion of the maxillary sinus, mandibular canal, or angled adjacent roots. Short implants have been shown to be as successful as standard length implants (>10 mm).14-16 Studies on short, single implants with amplified C/I showed no increased marginal bone loss compared to normal C/I.17-20 Studies on multiple short implants supporting a fixed prosthesis also found no effect of increased in C/I on marginal bone loss.21,22 Two systematic reviews concluded that amplified C/I resulted in less marginal bone loss than lower C/I.3,23 This result is contrary to the assumption that greater anchorage is beneficial to stability and force distribution, and should result in less harmful stress to crestal bone. Blanes attributed the improved marginal bone levels to the stimulatory effect of higher but not excessive stress to the supporting bone.23 Alveolar bone tolerance of amplified C/I may also be due to rough or porous implant surfaces and tapered, threaded, macroretentive design features that contribute to high initial torque and stability.24,25 Splinting should be considered when restoring multiple implants with amplified C/I to improve stress distribution in crestal bone. Splinting concentrates stress in the prosthesis connectors, reducing force to the peridontium.26 Splinting has been recommended for implants in poor quality bone to resist destructive horizontal forces.27,28 Splinting can also minimize the gingival embrasures by enlarging the interproximal contact height, whereas normal interproximal contacts would leave large gingival embrasures that trap food. Splinting is not required for normal C/I multiple implantsupported restorations.29 Nonsplinted posterior teeth crowns create a biomimetic restoration that allows normal access to flossing. They restrict prosthetic problems—such as porcelain fracture—that occur on a single tooth to just that tooth, whereas multiple splinted crowns are affected by a single problem tooth. Interproximal contact adjustment for these crowns is complicated by the ankylotic implant support compared to the PDL resiliency of teeth. A very tight contact may pass floss as the natural teeth 12 January/February 2015 General Dentistry Fig. 7. Cement-retained composite-acrylic provisional restoration No. 11 and splinted screw-retained composite provisional restoration No. 12-14 with amplified C/I. deflect on pressure, whereas this same contact with implant support would not permit floss to pass. Assiduous refinement of these contacts should be done with thin marking ribbon in the contacts to show the exact area to be adjusted. Implant-supported crowns require a very small space in the contact area so that floss can pass but food won’t get trapped. Heavy interproximal contacts can create a nonpassive cementation with increased bone strain, which magnifies the deleterious effects of occlusal loading.26 The current literature supports the use of single and multiple short implants to restore edentulous spaces with normal, reduced, and amplified C/I. Short implants expand the treatment planning options for the dental team, especially in atrophic posterior jaw sites with an amplified C/I. This option may allow a fixed prosthodontic solution for the patient where grafting, time, or financial concerns previously restricted treatment to a movable prosthesis. Author information Dr. Solow is in private practice in Mill Valley, California, and a visiting faculty member at the Pankey Institute, Key Biscayne, Florida. References www.agd.org 1. Grossmann Y, Sadan A. The prosthodontic concept of crown-to-root ratio: a review of the literature. J Prosthet Dent. 2005;93(60:559-562. 2. Keough B. Occlusal considerations in periodontal prosthetics. Int J Periodontics Restorative Dent. 1992;12(5):359-371. 3. Garaicoa-Pazmino C, Suarez-Lopez del Amo F, Monje A, et al. Influence of crown/implant ratio on marginal bone loss: a systematic review. J Periodontol. 2014;85(9):1214-1221. 4. Kim Y, Oh TJ, Misch CE, Wang HL. Occlusal considerations in implant therapy: clinical guidelines with biomechanical rationale. Clin Oral Implants Res. 2005;16(1):26-35. 5. Kraus BS, Jordan RE, Abrams L. A Study of the Masticatory System: Dental Anatomy and Occlusion. Baltimore, MD: The Williams and Wilkins Company; 1969. 6. Baggi L, Cappelloni I, Di Girolamo M, Maceri F, Vairo G. The influence of implant diameter and length on stress distribution of osseointegrated implants related to crestal bone geometry: a three-dimensional finite element analysis. J Prosthet Dent. 2008; 100(6):422-431. 7. Chang SH, Lin CL, Lin YS, Hsue SS, Huang SR. Biomechanical comparison of a single short and wide implant with monocortical or bicortical engagement in the atrophic posterior maxilla and a long implant in the augmented sinus. Int J Oral Maxillofac Implants. 2012;27(6):e102-e111. 8. Schulte J, Flores AM, Weed M, Crown-to-implant ratios of single tooth implant-supported restorations. J Prosthet Dent. 2007;98(1):1-5. 9. Misch CE, Steignga J, Barboza E, Misch-Dietsh F, Cianciola LJ, Kazor C. Short dental implants in posterior partial edentulism: a multicenter retrospective 6-year case series study. J Periodontol. 2006;77(8):1340-1347. 10. Merin RL. Repair of peri-implant bone loss after occlusal adjustment: a case report. J Am Dent Assoc. 2014;145(10):1058-1062. 11. Kerstein RB. Nonsimultaneous tooth contact in combined implant and natural tooth occlusal schemes. Pract Proced Aesthet Dent. 2001;13(9):751-755. 12. Gore E, Evlioglu G. Assessment of the effect of two occlusal concepts for implant-supported fixed prostheses by finite element analysis in patients with bruxism. J Oral Implantol. 2014;40(1):68-75. 13. Rompen E, Domken O, Degidi M, Pontes AE, Piattelli A. The effect of material characteristics, of surface topography and of implant components and connections on soft tissue integration: a literature review. Clin Oral Implants Res. 2006;17(Suppl 2):55-67. 14. Anitua E, Pinas L, Begona L, Orive G. Long-term retrospective evaluation of short implants in the posterior areas: clinical results after 10-12 years. J Clin Periodontol. 2014; 41(4):404-411. 15. Al-Hashedi AA, Taiyeb Ali TB, Yunus N. Short dental implants: an emerging concept in implant treatment. Quintessence Int. 2014;45(6):499-514. 16. Fugazzotto PA, Beagle JR, Ganeles J, Jaffin R, Vlassis J, Kumar A. Success and failure rates of 9 mm or shorter implants in the replacement of missing maxillary molars when restored with individual crowns: preliminary results 0 to 84 months in function. A retrospective study. J Periodontol. 2004;75(2):327-332. 17. Birdi H, Schulte J, Kovacs A, DDS, Weed M, Chuang SK. Crown-to-implant ratios of short-length implants. J Oral Implantol. 2010;36(6):425-433. 18. Schneider D, Witt L, Hammerle CH. Influence of the crown-to-implant length ratio on the clinical performance of implants supporting single crown restorations: a cross-sectional retrospective 5-year investigation. Clin Oral Implants Res. 2012;23(2):169-174. 19. Rossi F, Lang NP, Ricci E, Ferraioli L, Marchetti C, Botticelli D. Early loading of 6-mm short implants with a moderately rough surface supporting single crowns - a prospective 5-year cohort study. Clin Oral Implants Res. 2014 [Epub ahead of print]. 20. Lai HC, Si MS, Zhuang LF, Shen H, Liu YL, Wismeijer D. Long-term outcomes of short dental implants supporting single crowns in posterior region: a clinical retrospective study of 5-10 years. Clin Oral Implants Res. 2013;24(2):230-237. 21. Anitua E, Alkhraist MH, Pinas L, Begona L, Orive G. Implant survival and crestal bone loss around extra-short implants supporting a fixed denture: the effect of crown height space, crown-to-implant ratio, and offset placement of the prosthesis. Int J Oral Maxillofac Implants. 2014;29(3):682-689. 22. Pistilli R, Felice P, Cannizzaro G, Piatelli M, et al. Posterior atrophic jaws rehabilitated with prostheses supported by 6 mm long 4 mm wide implants or by longer implants in augmented bone. One-year post-loading results from a pilot randomised controlled trial. Eur J Oral Implantol. 2013;6(4):359-372. 23. Blanes RJ. To what extent does the crown-implant ratio affect the survival and complications of implant-supported reconstructions? A systematic review. Clin Oral Implants Res. 2009;20(Suppl 4):67-72. 24. Sohn DS, Lee JM, Park IS, Jung HS, Park DY, Shin IH. Retrospective study of sintered porous-surfaced dental implants placed in the augmented sinus. Int J Periodontics Restorative Dent. 2014;34(4):565-571. 25. Steigenga J, Al-Shammari K, Misch C, Nociti FH Jr, Wang HL. Effects of implant thread geometry on percentage of osseointegration and resistance to reverse torque in the tibia of rabbits. J Periodontol. 2004;75(9):1233-1241. 26. Guichet DL, Yoshinobu D, Caputo AA. Effect of splinting and interproximal contact tightness on load transfer by implant restorations. J Prosthet Dent. 2002;87(5):528-535. 27. Tiossi R, Lin L, Rodrigues RC, et al. Digital image correlation analysis of the load transfer by implant-supported restorations. J Biomech. 2011;44(6):1008-1013. 28. Wang TM, Leu LJ, Wang JS, Lin LD. Effects of prosthesis materials and prosthesis splinting on peri-implant bone stress around implants in poor-quality bone: a numeric analysis. Int J Oral Maxillofac Implants. 2002;17(2):231-237. 29. Simon RL. Single implant-supported molar and premolar crowns: a ten-year retrospective clinical report. J Prosthet Dent. 2003;90(6):517-521. www.agd.org General Dentistry January/February 2015 13 Endodontics Achieving and maintaining apical patency in endodontics: optimizing canal shaping procedures Rich Mounce, DDS A chieving and maintaining apical patency is a prerequisite for predictable clinical results in endodontic treatment. After endodontic access, cleaning and shaping of root canal systems is made possible by negotiation of canals to their apical terminus followed by the creation of a glide path and nickel titanium instrumentation. Leaving untreated canal space due to a lack of apical patency is the harbinger of iatrogenic misadventure (canal transportation) as well as long-term endodontic failure. The benefits of achieving and maintaining apical patency include improved removal of organic and inorganic debris from the root canal system. It is axiomatic that optimal debris removal from the canal system increases postoperative comfort relative to the alternatives (such as loss of working length, uncleaned and unfilled canal space, and iatrogenic canal transportation). The minor constriction (MC) of the apical foramen is the ideal end point of instrumentation, irrigation, and obturation during clinical endodontic treatment. Anatomically, the MC is the narrowest diameter of the canal before it exits to the apical tissues. While apical anatomy can vary, and some canals do not have a true “narrowest diameter,” there is an optimal endpoint to which canal systems should be cleaned and obturated—most often, the MC. Leaving the MC at its original position and size is central to fulfilling the various objectives of endodontic cleaning and shaping goals, which include keeping the canal in its original position and creating a tapered funnel with narrowing cross sectional diameters moving from orifice to apex. For practical purposes, the MC is the anatomic landmark delineated by a 0.0 reading on electronic “apex” locators. Location of the MC and maintenance of apical patency provides the clinician a reproducible landmark for all cleaning, shaping, and obturation procedures. Should the true working length (TWL) change in treatment for any reason (especially electronically), the clinician should immediately troubleshoot the source of the differential. Any loss of TWL during a clinical procedure should alert the clinician both to the need for regaining the lost length and reconfirmation of the TWL before moving forward. An increase in TWL should alert the clinician to the possibility that the TWL was inaccurately determined initially. Once apical patency is obtained and reproducible, the canal can be predictably enlarged to prepare a glide path before the introduction of nickel titanium instruments for bulk canal shaping. A glide path is prepared when a No. 15 hand K file spins freely in the canal. Not all canals are negotiable to the MC. Severe 3-dimensional (3D) curvature, blockage, previous canal transportation, and calcification are natural barriers to the attainment of apical patency. An incorrectly and improperly used hand file (wrong file type, size, and/or pre-curvature) and inadequate coronal access, along with a lack of irrigation and viscous chelating agents can all leave otherwise negotiable canals without proper exploration and enlargement. Alternatively, using the correct hand file with optimal technique, access, irrigation, and Fig. 1. Radiograph showing tooth No. 18 at severe risk for canal blockage and nickel titanium instrument fracture if canal negotiation is not carried out appropriately. Note that tooth No. 19 has untreated canal space and coronal leakage present from the previous root canal treatment. 14 January/February 2015 General Dentistry www.agd.org Fig. 2. Tooth No. 18 post-treatment. Fig. 3. A clinical case treated using the concepts utilized in this column. Fig. 4. A clinical case treated using the concepts utilized in this column. sequencing improve the possibilities for canal negotiation. In general terms, the more curved and calcified a canal, the greater the time and attention to detail required for negotiation. Simpler anatomy is generally more forgiving, in that small errors in clinical judgment may not lead to severe iatrogenic issues (Fig. 1 and 2). While a comprehensive review of all canal anatomy requiring preoperative evaluation prior to treatment is beyond the scope of this column, it is important to note that special care should be taken to obtain a comprehensive radiographic assessment of the tooth prior to making treatment-planning decisions. For clinicians using 2-dimensional (2D) radiographic technology, this means having multiple radiographic angles to guide the assessment of calcification and curvature. Cone beam computed tomography assessment is the gold standard for radiographic anatomic evaluation. Regardless of whether the clinician is using 2D or 3D imaging, the true anatomy of the canal cannot be fully known until the canal is being negotiated with hand files. Aside from obvious calcification and curvature, many clinical entities, including high furcations, crowns obscuring the furcation, rotated and tipped teeth, atypical root numbers and canal morphology—such as C-shaped lower second molar canal configurations and lower molars with either a third or fused root—should inspire caution in the clinician with regard to the complexity of the canal space being explored. Hand files give the clinician strong clues to the complexity of the root canal system. For example, if a hand file emerges from a root with a 3D curve imparted onto it, the clinician literally has an impression of the canal shape. This knowledge has ramifications for the clinician with regard to glide path size, the means for creating the glide path, and nickel titanium sequencing, among others. Aside from optimal visualization and magnification (surgical microscope and/or loupes), removal of the cervical dentinal triangle, restrictive dentin in the coronal third, and pulp chamber debris all set the stage for hand file negotiation. It is advisable during evacuation of the pulp chamber and coronal third to apply a viscous EDTA gel to emulsify pulp tissue and hold it in suspension while the aforementioned removal of pulp tissue is taking place in the coronal third prior to apical negotiation. Clinical technique Clinically, a precurved No. 6 hand K file is used first to the TWL followed by No. 8, 10, 12, and 15 files. Once a hand K file reaches the MC, it can be safely and efficiently reciprocated with a reciprocating handpiece that replicates the watch winding motion of the manual hand file technique while saving time and hand fatigue. If a more stiff file is required for canal negotiation, several marketplace options are available. Once apical patency is obtained, the importance of frequent recapitulation cannot be overstated. Frequent recapitulation is critical in apical irrigation and cleansing. It involves the insertion of a small hand file to assure the clinician that the canal is open and negotiable. Clinically, after every insertion of a nickel titanium file, a small hand file should be inserted to ensure the canal is open and negotiable to the MC. As the recapitulating hand file moves out of the canal, fresh irrigant should move apically (Fig. 3 and 4). This column has discussed the importance of achieving and maintaining apical patency. Emphasis has been placed on assessing the anatomy of the clinical case preoperatively and moving sequentially to determine the position of the minor constriction of the apical foramen.1-3 Future columns may address specific techniques for hand file negotiation and achieving apical patency in curved and calcified canals. Author information Dr. Mounce is in endodontic practice in Rapid City, South Dakota. He has written and lectured globally on endodontics. Disclaimer Dr. Mounce owns MounceEndo, LLC, which markets the rotary nickel titanium MounceFile in Controlled Memory and Standard NiTi. References 1. Dummer PM, McGinn JJ, Rees DG. The position and topography of the apical constriction and apical foramen. Int Endod J. 1984;17(4):192-198. 2. Meder-Cowherd L, Williamson AE, Johnson WT, Vasilescu D, Walton R, Quian F. Apical morphology of the palatal roots of maxillary molars by using micro-computed tomography. J Endod. 2011;37(8):1162-1165. 3. Burch JG, Hulen S. The relationship of the apical foramen to the anatomic apex of the tooth root. Oral Surg Oral Med Oral Pathol. 1972;34(2):262-268. www.agd.org General Dentistry January/February 2015 15 Diagnosis and Treatment Planning Why the general dentist needs to know how to manage oral lichen planus Stephanie M. Price, DDS n Valerie A. Murrah, DMD, MS Oral lichen planus (OLP) is a frequently mismanaged chronic disease that requires care throughout a patient’s life, and therefore a condition the general dentist must know how to manage. Patients with OLP often suffer considerable physical discomfort and an inability to perform proper oral hygiene, eventually resulting in poor periodontal health. In addition, these patients are confronted with the psychological stress of knowing that OLP is not curable. This is accompanied by a fear of other negative health developments, particularly oral cancer. The objective of this study was to identify major issues surrounding the management of OLP by the general dentist. A literature review of over 1100 articles was performed. An eclectic compilation of the issues revealed 12 major areas of concern. This article reviews those concerns and presents strategies for coping with S ince Erasmus Wilson first described oral lichen planus (OLP) in 1869, much has been written about the condition.1 Oral lichen planus affects 0.5%-2% of the population, with a predominance in women 30-70 years of age.2-7 Clinically, OLP manifests most frequently bilaterally, with the most common sites being the buccal mucosa, tongue, and gingiva.8-14 It has several forms; the most commonly described are reticular (containing Wickham’s striae) and erosive (Fig. 1 and 2).9,11,14-17 While the etiology of OLP is unknown, it is thought to be a T-cell-mediated autoimmune response.10,18-23 The authors present January/February 2015 Key words: lichen planus, dental management, malignant transformation, general dentist compelling reasons for the general dentist to become thoroughly knowledgeable about this uncommon disease and to keep current on the latest issues regarding OLP throughout his/her professional life. The dentist who is able to diagnose, treat, and manage an OLP patient may not only improve the quality of, but may also potentially prolong, the patient’s life. Materials and methods Citations and abstracts of over 1100 articles were reviewed regarding all aspects of lichen planus to identify critical issues pertinent to the management of the OLP patient by the general dentist. Fig. 1. Reticular lichen planus with intersecting white net-like lines (Wickham’s striae) with focal ulceration showing an erosive component. 16 the myriad signs, symptoms, and complications associated with this disease, as well as educational approaches and legal considerations. A rationale is provided to place the responsibility for the management of these patients under the person best positioned to coordinate care for this condition—the general dentist. A general dentist can contribute to the overall oral health of an OLP patient with timely diagnosis, effective treatment, thorough patient education, and the orchestration of efforts by a team of health care providers. Received: June 24, 2013 Accepted: August 13, 2013 General Dentistry Results Twelve broad areas of concern for the general dentist were identified in an effort to promote a proactive approach in the management of this disease. These are listed in Table 1. Discussion Clinical presentation and identification The dentist may identify signs and symptoms suggestive of OLP upon meeting a new patient or during routine follow-up examinations. Occasionally, a new patient may present with signs and symptoms of OLP as his or her chief complaint. OLP can Fig. 2. Erosive lichen planus in addition to significant plaque accumulation. www.agd.org Table 1. Twelve areas of concern for the general dentist in the treatment of an oral lichen planus (OLP) patient. 1. Recognition of clinical signs and symptoms 2. Optimal objective diagnosis 3. Disease management and concomitant reduction of the patient’s pain and suffering 4. Reduction in risk of increased periodontal disease or exacerbation of existing periodontal disease 5. Education of the patient concerning his/her disease and management of his/her expectations 6. Appropriate referral of patient to other health care providers for skin, nail, or genital lesions Table 2. Partial list of medications linked to lichenoid reactions.39-42 Antihypertensives Diuretics 7. Identification of correlated systemic diseases (hepatitis C or graft versus host disease) Methyldopa 8. Avoiding the misfortune of mistakenly treating a patient as though he/she has OLP when he/she has oral cancer ACE inhibitor β-blocking agent 9. Identification of malignant transformation early, when it can be managed with minimal morbidity and mortality Antimalarials Oral hypoglycemic drugs 10.Dentist versus physician management Phenothiazines 11.Reduction of susceptibility to litigation Gold salts 12.Orchestrating the coordination of care HIV antivirals be asymptomatic; this is usually associated with the reticular type. It may also present with a burning sensation; this is typically associated with the erosive type. The presentation can change within one patient over time and these changes could be associated with increased stress, thus making successful symptom management challenging.9,10,14,24-29 Diagnosis OLP can present with clinical and histologic presentations similar to many other conditions, such as lichenoid drug reactions (also known as lichenoid drug eruptions), lichenoid contact mucositis, cinnamon stomatitis, lupus erythematosus, dysplasia, carcinoma, and graft versus host disease—all of which require different treatments.9,10,15,30-32 Because OLP does not have a pathognomonic appearance—except for classical Wickham’s striae—diagnosis by biopsy is necessary. Additionally, the practitioner must keep in mind that multiple pathologies can exist simultaneously in the same or in different locations, thus complicating both diagnosis and treatment.9,33,34 Histopathological criteria include variable keratinization, Fig. 3. Photomicrograph of an epithelial rete ridge showing attenuation, interface change (lyphocytic migration into the epithelium), and florid lymphocytic infiltrate in the upper connective tissue (H&E, magnification 400X). NSAIDs basal cell layer liquefaction, and a bandlike T-cell lymphocytic infiltrate localized to the lamina propria proximal to the epithelium.35,36 Other features often present are interface change characterized by the movement of inflammatory cells into the epithelium, Civatte (colloid) bodies, and saw-toothed (attenuated) rete ridges (Fig. 3).10,35-37 The findings of the clinician and pathologist should always be correlated when making a diagnosis. A clinical photograph should ideally be sent with the biopsy to the lab, and the clinician should consult the pathologist if the diagnosis does not fit the clinical context. Specimens should be submitted in formalin for routine microscopy and in Michel’s solution for direct immunofluorescence (DIF). The DIF specimen may be critical in differentiating OLP from other vesiculo-ulcerative diseases such as benign mucous membrane pemphigoid, lupus erythematosus, pemphigus vulgaris, chronic ulcerative stomatitis, and lichenoid reactions. Under DIF, OLP lesions often show fluorescence at the level of the basement membrane zone with antibodies to fibrinogen and, less frequently, to IgG and IgM.10,23,38 www.agd.org Differential diagnoses Lichenoid drug reactions may be more difficult to manage since the removal of a given medication may threaten the patient’s overall health. In addition, these reactions are more difficult to recognize because manifestations may be delayed for weeks to months, both at the start of medication and/or after the medication has been stopped.39-42 The clinician should take a detailed health history and inquire about allergies and medications commonly associated with lichenoid drug reactions (Table 2). A potential lichenoid drug reaction that merits further investigation is the use of hydrochlorothiazide in patients who have experienced sulfa allergies. Hydrochlorothiazide is the most commonly prescribed antihypertensive, and treatment with this drug is commonly associated with lichenoid mucositis.43 Patients with sulfa allergies often have a history of a hypersensitivity response to the sulfonamide antibiotic, sulfamethoxazole-trimethoprim.44-46 Although there is little evidence that antimicrobial sulfonamides cross-react with other sulfur General Dentistry January/February 2015 17 Diagnosis and Treatment Planning Why the general dentist needs to know how to manage oral lichen planus Table 3. Steroid treatment for OLP. Fig. 4. An example of a focal lichenoid reaction to amalgam. The lesion resolved following replacement of the amalgam with a gold crown. Systemic Topical Methylprednisolone 0.1% Triamcinolone-mild potency Prednisone 0.05% Fluocinonide-moderate potency 0.05% Clobetasol-high potency Topical steroids could be applied in a custom tray worn at night. Table 4. Recommended care sequence for an OLP patient. containing moieties, patients with sulfa allergies may be predisposed to lichenoid reactions from medications containing sulfur groups such as hydrochlorothiazide and sulfonylureas (non-antimicrobial sulfonamides).44,45,47,48 Alternatively, patients who have a sulfa allergy may simply have a predilection to other allergic responses even with chemically dissimilar drugs.48 This is not surprising given the great number of medications associated with oral lichenoid reactions. Unlike a lichenoid drug reaction, lichenoid contact mucositis can be differentiated clinically by the position of the lesion next to the offending agent (e.g., amalgam, gold, composite, or cast alloy restorations).10,31,49-56 The dental material most often cited as the cause of a hypersensitivity reaction is amalgam (Fig. 4).51,52,54-56 Some authors advocate removing restorations for resolution of this hypersensitivity, while other authors do not.49,51,57 Although not a dental material, cinnamon is an even more frequent cause of a mucositis resembling lichen planus.32,58 There is controversy— with both amalgam and cinnamon—over the benefit of allergy patch testing.31,32,49 Points of contention include which mercurial or amalgam material to use for the testing, the clinical similarity between sensitivity and irritant responses, the length of time that the material should be in contact with the skin, and the relevance of cutaneous testing to mucosal allergies.31,32 Complicating the diagnosis regarding amalgam are other factors such as the contour of a restoration or the position of its margin. With respect to cinnamon, discontinuation 18 January/February 2015 1. Health history 2. Clinical exam 3. Working diagnosis 4. Biopsy (for light microscopy and DIF) 5. Definitive diagnosis 6. Patient education 7. Referral to primary care physician, if applicable of the use of the product or food containing cinnamon should result in resolution of the lesions in a matter of days. Treatment Following the determination of the diagnosis, management can be accomplished in a number of ways depending on the severity of disease. The usual first line of treatment for symptomatic OLP is topical steroids (Table 3). Approaches to treatment could also include an initial systemic steroid burst, such as a methylprednisolone or a high potency topical corticosteroid, such as clobetasol propionate. Maintenance treatment during symptomatic periods could be a moderate topical steroid, such as fluocinonide. Triamcinolone, a mild topical steroid, is occasionally used but often does not result in significant resolution in adults. Treatment of more severe cases consists of systemic steroids or other immunosuppressant agents. Topical drug delivery via a custom tray or mouthguard—even if lesions extend beyond the gingiva—has been shown to be efficacious, General Dentistry www.agd.org 8. Treatment (to include topical and/or systemic steroids and increased frequency of dental prophylaxis) 9. Re-evaluation of treatment 10. Treatment modification and additional biopsy as needed 11. Periodic follow-up to check for malignant transformation particularly at nighttime, as the drug will leak out of the tray and bathe the oral tissues. Treatment of symptoms can be accomplished with viscous lidocaine or other topical anesthetics. A recommended care sequence for an OLP patient is illustrated in Table 4. Associated candidiasis Since steroid treatment suppresses the immune system, it may also promote the development of a Candida infection that will exacerbate the patient’s discomfort. It is also possible that a Candida infection was already present prior to steroid treatment for OLP.13,59 If candidiasis is suspected, clinicians should obtain a cytologic smear, and patients with positive results should be given appropriate antifungal treatment, such as fluconazole, clotrimazole, or nystatin (Table 5). In addition to alleviating additional patient symptoms, it is helpful to have possible Candida infections cleared prior to performing a biopsy so that only the inflammation specific to OLP is evident in the specimen. dentists may potentially learn more about patients’ individual clinical presentations and can make appropriate referrals. Table 5. Antifungal treatment for associated candidiasis in OLP patients. Systemic Topical Fluconazole 100-200 mg Clotrimazole 10 mg troches Nystatin 100,000-200,000 units Topical antifungals could be administered as troches or as lozenges. Chart. Network of providers for management of oral lichen planus. Periodontist Oral Surgeon Gynecologist or Urologist General Dentist Oral Pathologist Primary Care Physican Dermatologist Otolaryngologist Relationship to periodontal health One of the most significant reasons for the general dentist to be knowledgeable about OLP is that it can have a negative impact on periodontal health. It is estimated that approximately 38%-48% of OLP patients have gingival lesions, and 7%-10% have gingival lesions as their only clinical manifestation.11,14,60,61 It is thought that plaque and calculus exacerbate the clinical presentation of OLP.11,60,62-64 All OLP types are associated with increased bleeding on probing, which is expected given the inflammatory nature of the disease.11,62,64 OLP patients with symptomatic lesions often have difficulty with oral hygiene and have more plaque and calculus present, putting them at increased risk for poor periodontal health.60,63 Patients with erosive lichen planus have more clinical attachment loss.63 Avoiding certain types of foods, such as those that are acidic, spicy, and/or rough textured; using a nonalcoholic chlorhexidine rinse; and placing patients on a more frequent recall schedule may be helpful.31,63 Trauma, heat, irritants from smoking, and oral habits have also been found to exacerbate the clinical symptoms of OLP.10,31 Education Educating OLP patients is essential to both short- and long-term treatment success. A 1997 survey conducted to determine patient awareness of OLP etiology, treatment, and malignancy resulted in a wide variety of responses.65 The authors found a significant number of patients reporting the treatment strategy of “learn to live” with the disease, and only 7% of the respondents stating that they received additional education after the initial diagnosis.65 By providing education to their OLP patients, dentists make them aware of potentially exacerbating factors, help them understand the need for increased visits to the dental office and improved home care, and raise awareness of other associated health concerns. According to Burkhart et al, it is important that dentists inform their patients about all the pertinent information regarding this disease, and provide them with a comprehensive treatment strategy.65 By doing so, dentists can reduce OLP patients’ inherent stress of uncertainty and empower them to be part of their own health success.65 In addition, during the educational process, www.agd.org Presentation in areas outside of the oral cavity Lichen planus not only presents in the oral cavity, but also can be found in the mucous membranes of the genitalia, esophagus, skin, nails, and eyes.3,66-73 Approximately 19%-25% of OLP patients have genital lesions.70 In these patients, OLP tends to present primarily on the gingiva.66,68,70 Most of the literature describes women with vulvovaginal-gingival lichen planus, however there are also a few reports of male patients, for whom the lesions are referred to as penogingival lichen planus.66,70 Ten percent to 20% of OLP patients have cutaneous lesions, and it has been found that patients with cutaneous lesions either already have or are likely to develop OLP.3,70,74 The sequence of presentation between OLP and lichen planus in other locations is not predictable, and presentations may be separated by months or years.3,69,70 Lichen planus presenting in the fingernails, toenails, esophagus, and eyes is uncommon; in a study of 584 lichen planus patients, 11 showed clinical signs of nail involvement, 6 presented with esophageal involvement, and 1 had biopsy-proven ocular lichen planus.70 Because any given clinician does not investigate all potential anatomic sites of lichen planus, the condition is frequently misdiagnosed, particularly in the genitalia.69,70 Therefore, the general dentist must be able to provide effective referrals to gynecologists, urologists, and dermatologists (Chart). If these alternate presentations are missed during the health history, the general dentist could discuss the possibility of other lichen planus lesions as part of patient education. Associated conditions Oral lichen planus may signal the clinician to look for hepatitis C, as it is another systemic condition found to be associated with the disease.75-77 A previous worldwide estimate found that 170 million people have chronic hepatitis C, although its prevalence is regionally variable.78 Many hepatitis C patients may be asymptomatic.79 Chronic hepatitis C can lead to hepatocellular carcinoma and to cirrhosis, General Dentistry January/February 2015 19 Diagnosis and Treatment Planning Why the general dentist needs to know how to manage oral lichen planus which itself could be an independent risk factor for oral cancer.30,80 A person with hepatitis C is 2.8-5.4 times more likely to have OLP than the control population.57 Therefore, it makes good sense to ensure that one’s health history includes questions that address hepatitis C risk factors and to refer patients to their primary care providers as indicated.57 In the United States, risk factors for hepatitis C include blood transfusions, intravenous drug use, or high risk sexual practices; worldwide practitioners should look for risk factors specific to their region.31,78 Several authors postulate that it is not economically advantageous for everyone who has OLP to be screened for hepatitis C.31,57 Regional areas that tend to have strong associations between OLP and hepatitis C are the Mediterranean region of Europe (especially Spain and Italy) and East Asia (especially Japan).10,57,75,76 Lichenoid reactions as a manifestation of graft versus host disease may be the easiest of systemic conditions to identify due to their presentation after bone marrow or stem cell transplants.81,82 Oral complications are common and associated with donor-generated T cells attacking host tissues.31,82-84 The reaction can be found in more severe cases of acute graft versus host disease (<100 days), but historically is a frequent finding in chronic disease.84-86 Dentists should notify the patient’s transplant physician should these lesions manifest in the oral cavity so as to integrate oral symptom management with overall disease treatment. As with other symptomatic lichenoid reactions, these patients can be treated with topical corticosteroids and/or topical anesthetics.84 Malignant transformation Officially, OLP has been designated as a premalignant condition by the World Health Organization; however the rates and mechanisms of transformation are subject to debate.30,87-91 Researchers who theorize that OLP is not a premalignant condition propose that cases diagnosed as malignant transformation of OLP were actually instances of misdiagnosed epithelial dysplasia.9,91,92 Published rates of malignant transformation vary from 0%-12.5%.30,87,91 Clinicians should become particularly suspicious of malignant transformation when there are specific sites with a loss of homogeneity, increased size or 20 January/February 2015 asymmetric appearance of the lesion, and lack of response to treatment.30,60 Treatment of patients with a diagnosis of OLP should include a clinical examination every 3-6 months for a minimum of 5 years, ideally with regular photographic documentation of the lesion.30 Several studies have found that the tongue is the preferred site for malignant transformation, although all areas should be observed with suspicion.30,87 One review article found that the reported interval between a diagnosis of OLP and oral squamous cell carcinoma ranges from 20.8 months to 10.1 years.30 Recent research hypothesizes that malignant transformation of OLP is related to long-term chronic inflammation.89 In addition to the increased rate of cellular turnover, the thought is that the nitric oxide produced by inflammatory cells can promote carcinogenesis.90 Some researchers have hypothesized that steroid and/or immunosuppressive treatment contributes to the potential for carcinogenesis in OLP, although there is no current evidence to support this.30,38,87 Late diagnosis of oral cancer will likely result in a patient’s increased morbidity and mortality. The ideal period from diagnosis to treatment of oral cancer is the sooner the better. A 10-year analysis of new cases of oral squamous cell carcinoma showed that there was a significant difference in the stage of the tumor, and therefore prognosis, between those referred earlier than 6 weeks and those later.93 In 2000, the United Kingdom placed a “2-week” rule for all suspected cancers as a time limit for referral from primary care to a specialist.93 Respective roles of dentists and physicians in oral examination Dentists are in the best position to identify and diagnose all diseases of the oral cavity. As specialists of the oral cavity, dental practitioners spend more time observing this area and thus would be more likely to observe a soft tissue irregularity or to diagnose a chief complaint associated with an oral mucosal lesion. While physicians are often aware of oral diseases and understand their implications to overall health, they are less likely to perform oral exams than dentists.94 In a 1995 survey conducted in Maryland of dentists and physicians, more physicians than dentists felt that they did not feel adequately trained to conduct oral General Dentistry www.agd.org cancer exams.95 A similar 2009 survey in Massachusetts found that dentists performed double the number of oral cancer exams compared to physicians.94 This study also found that 24% of dentists reported finding suspicious lesions in >10 patients, compared to no physicians finding such lesions in >10 patients.94 The study further reported that both dentists and physicians are more confident that dentists are qualified to perform oral cancer exams when compared to physicians.94 The hypothetical correlation is that OLP would be found in the same exam conducted to detect oral cancer, and that physicians may be even less aware of specific uncommon diseases of the oral cavity—such as OLP—than they are of oral cancer. If physicians are less likely to perform oral exams, they are consequently less likely to manage oral lesions. In addition, because of the association between OLP and periodontal disease, dentists are in the best position to manage the entire oral health picture. Dentists are also more likely to fabricate a custom tray for drug delivery. This is not to suggest, however, that physicians or other primary care providers should not conduct comprehensive oral exams, with the goal of identifying lesions, as it is well-recognized that some patients visit their primary care providers more frequently than their dentist or do not visit a dentist at all. Therefore, it is essential that a comprehensive examination of the mouth be taught in the medical school clinical curriculum. A survey of 86 US medical schools found that such training is currently brief and incomplete.96,97 The Association of American Medical Colleges recommends that additional training be added to the medical curriculum in its Medical Schools Objective Project.98 Litigation Litigation involving oral cancer and OLP is not openly discussed. Consequently, there is a dearth of information published in the medical literature. However, selected publications on the subject merit the general dentist’s attention. Given that OLP is a disease that is relatively uncommon, it is frequently misdiagnosed, resulting in a number of lawsuits for “failure to diagnose oral cancer” as the health care provider makes the unfortunate mistake of treating a patient as though he/she has OLP when he/she actually has oral cancer.99 The top 3 allegations in oral cancer lawsuits are failure to diagnose, failure to biopsy, and failure to refer.100 Furthermore, patients who have had delays in treatment resulting in poor outcomes are more likely to sue.100,101 While there are many opportunities for delays (such as a patient failing to return for routine exams or a patient’s hesitation in making an appointment with a specialist), general dentists can minimize the amount of time taken to obtain a definitive diagnosis and proceed to treatment. This time element is the most relevant in avoiding a lawsuit.93 Additionally, an increased time to diagnosis may result in a less successful legal defense. A review of oral cancer lawsuits determined that if the delay in diagnosis was <3 months, 86% of defendants (practitioners) were successful, however if the delay was >3 months, only 40% were successful.100 In their review of litigation involving delayed diagnosis of cancer, Rice & Hamburger noted a rapid decline in the ability for a defendant to succeed in cases of >3 months delay and found that after 6 months delay, the length of the delay or the survival of the patient is irrelevant in the jury’s findings.102 Summary With the risk for development of malignancy, associated medical disorders, and the severe symptoms often associated with the disease, optimal management of OLP is requisite for the accomplished practitioner. There are still unanswered questions about OLP; however, by using a comprehensive treatment approach to clinical symptoms and oral health maintenance patients will experience better outcomes. In conclusion, the general dentist is in the best position to contribute in the most meaningful way to the overall well-being of the OLP patient by timely diagnosis, effective treatment, and thorough patient education; and by doing what a general dentist does best—orchestrating the coordination of care by a team of diverse medical and dental providers. Author information Dr. Price is a doctoral alumna, University of North Carolina School of Dentistry, Chapel Hill, where Dr. Murrah is a professor and chair, Department of Diagnostic Sciences, and director, Oral and Maxillofacial Pathology. References 1. Wilson E. On lichen planus. J Cutan Med Dis Skin. 1869;3:117-132. 2. Axell T, Rundquist L. Oral lichen planus—a demographic study. Community Dent Oral Epidemiol. 1987;15(1):52-56. 3. Andreasen JO. Oral lichen planus. 1. A clinical evaluation of 115 cases. Oral Surg Oral Med Oral Pathol. 1968;25(1):31-42. 4. Brown RS, Bottomley WK, Puente E, Lavigne GJ. 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Oral lichen planus as a preneoplastic inflammatory model. J Biomed Biotechnol. 2012;2012: 759626. 90. Liu Y, Messadi DV, Wu H, Hu S. Oral lichen planus is a unique disease model for studying chronic inflammation and oral cancer. Med Hypotheses. 2010;75(6):492-494. 91. Position paper: oral features of mucocutaneous disorders. J Periodontol. 2003;74(10):1545-1556. 92. Kaugars GE, Svirsky JA. An update on the dysplastic/ carcinomatous transformation of oral lichen planus. J Oral Med. 1982;37(3):75-79. 93. Pitchers M, Martin C. Delay in referral of oropharyngeal squamous cell carcinoma to secondary care correlates with a more advanced stage at presentation, and is associated with poorer survival. Br J Cancer. 2006;94(7):955-958. 94. Applebaum E, Ruhlen TN, Kronenberg FR, Hayes C, Peters ES. Oral cancer knowledge, attitudes and practices: a survey of dentists and primary care physicians in Massachusetts. J Am Dent Assoc. 2009;140(4):461-467. 95. Yellowitz JA, Goodman HS. Assessing physicians’ and dentists’ oral cancer knowledge, opinions and practices. J Am Dent Assoc. 1995;126(1):53-60. 96. Ferullo A, Silk H, Savageau JA. Teaching oral health in U.S. medical schools: results of a national survey. Acad Med. 2011;86(2):226-230. 97. Ahluwalia K, Ro M, Erwin K, Treadwell H. Racial disparities in oral cancer risk and outcomes. J Cancer Educ. 2005;20(2):70-71. 98. Association of American Medical Colleges. Report IX Contemporary Issues In Medicine: Oral Health Education for Medical and Dental Students. Available at: https://www.mededportal.org/download/ 258678/data/oralhealthmsop.pdf. Accessed November 3, 2014. 99. Krutchkoff DJ, Eisenberg E. Dying of cancer: a patient’s recollection of her illness and of her doctors. Oral Surg Oral Med Oral Pathol. 1991;71(4):401-406. 100. Lydiatt DD. Cancer of the oral cavity and medical malpractice. Laryngoscope. 2002;112(5):816-819. 101. Lydiatt DD. Medical malpractice and head and neck cancer. Curr Opin Otolaryngol Head Neck Surg. 2004; 12(2):71-75. 102. Rice PJ, Hamburger J. Oral lichenoid drug eruptions: their recognition and management. Dent Update. 2002;29(9):442-447. Microbiology Investigation of antibacterial efficacy of Acacia nilotica against salivary mutans streptococci : a randomized control trial Devanand Gupta, BDS, MDS n Rajendra Kumar Gupta, PhD This double-blind, randomized control trial sought to evaluate the clinical effects of 3 mouthrinses against salivary mutans streptococci (MS). Ninety high-caries risk volunteers were randomly assigned to 3 groups, each group using a selected mouthrinse BID for 30 days. Subjects in Group 1 rinsed with 10 ml of 50% Acacia nilotica, Group 2 subjects rinsed with 10 ml of 0.2% chlorhexidine (active control), and subjects in Group 3 rinsed with saline water (passive control). Unstimulated saliva samples were collected at baseline, 30, and 60 days. MS were cultured on mitis salivarius bacitracin agar, and colony counts were obtained. The margin D ental caries is one of the most prevalent infectious diseases in humans worldwide.1 Caries is defined as a localized, progressive demineralization of the hard tissues of the crown and/or root surfaces of teeth. This demineralization is caused by acids produced by bacteria, particularly mutans streptococci (MS), which ferment dietary carbohydrates. This occurs within dental plaque, a bacteria-laden gelatinous material that adheres to tooth surfaces and becomes colonized by bacteria. Thus, caries results from the interplay of 3 factors over time: dietary carbohydrates, cariogenic bacteria within dental plaque, and susceptible hard tooth surfaces.1 If left untreated, caries may lead to pain, infection, and tooth loss. During the past few decades, changes have been observed in the prevalence and epidemiology of dental caries.1 Mouthrinses are adjuncts to mechanical plaque control and serve as delivery vehicles for antimicrobial agents. For decades, chlorhexidine has been considered the ‘gold standard’ among the different antimicrobial mouthrinsees commercially available.2 Although chlorhexidine is effective in reducing the number of MS, it has inherent side effects, such as staining of teeth and composite restorations, altered taste perception, metallic taste, and burning sensation.3 Plant compounds can be therapeutic substitutes for synthetically created antimicrobial agents.4 of error was fixed at 5%. ANOVA and post hoc least significant difference tests were performed. There were significant decreases in the MS colony count in the A. nilotica and chlorhexidine groups at 30 days (85% and 83%, respectively) and at 60 days (65% and 63%, respectively) (P < 0.0001). The antibacterial action of A. nilotica against MS was similar to that of chlorhexidine. Received: November 12, 2013 Revised: April 2, 2014 Accepted: May 7, 2014 Acacia species—commonly known as Babool (or babul), Egyptian mimosa, Egyptian thorn, kikar, Indian gum, and red thorn—have long been used for the treatment of various ailments and for other practical uses. The wood of A. nilotica was used by ancient Egyptians to make statues and furniture. Its use has been reported since early Egyptian dynasties. Dioscorides, the Greek physician considered to be the father of botany, described the use of A. nilotica (as a preparation extracted from the leaves and fruit pods) in his De Materia Medica.5 He named it akakia, and it is from this word that the modern name, acacia, is derived. The origin of the word, acacia, is “spiny,” which is a typical feature of the species. The species is widely spread in Africa, with a range extending from Egypt to Mauritania southwards to South Africa, and also in Asia, ranging eastwards to Pakistan and India. It has been introduced in China, Australia (where it is considered to be a pest plant of national importance), Caribbean and Indian Ocean islands, United States, Central America, and South America. It has been introduced as a medicinal, forage, and fuel wood plant in many parts of world. A. nilotica has been proven as an effective medicine in the treatment of malaria, sore throat (aerial part), toothache (bark), acute diarrhea, colds, bronchitis, diarrhea, bleeding hemorrhoids, and leucoderma.6 A. nilotica twigs have been used as toothbrushes.6 www.agd.org Considerable efforts have been made to find an active agent against Streptococcus mutans, as it is found to be resistant to many antibacterial agents, such as penicillin, amoxicillin, cefuroxime, and erythromycin.7 Thus, there is a growing need to investigate natural antimicrobial agents that are effective and safe for patients. A. nilotica mouthrinses have demonstrated effective antibacterial effects against halitosis-inducing bacteria on the tongue, and has also been used in the treatment of gingival bleeding and mouth ulcers.8 The antimicrobial efficacy of A. nilotica against MS has been ascertained in previous in vitro studies.9,10 However, no in vivo studies have been carried out to assess the antibacterial efficacy of A. nilotica against MS in comparison with chlorhexidine. Hence, the current study was conducted. Materials and methods This double-blind, randomized control trial was conducted on undergraduate student volunteers in the Department of Public Health Dentistry, Teerthankar Mahaveer Dental College and Research Centre, India. The protocol was approved by the Institutional Review Board (IRB) of Teerthankar Mahaveer University. All subjects signed an IRB-approved consent form. A pilot study was done on 10 patients from each of 3 test groups to check the feasibility of the study; those results are not included in the study. General Dentistry January/February 2015 23 Microbiology Investigation of antibacterial efficacy of Acacia nilotica against salivary mutans streptococci Table 1. Baseline background of the subjects. A. nilotica n = 30 Chlorhexidine n = 30 Placebo control n = 30 P value 15/15 10/20 12/18 0.698 Range of age (years); mean (SD) 20-24; 22.16 (2.01) 19-25; 21.42 (2.07) 20-25; 22.74 (2.28) 0.362 Number of times toothbrushing Once–25, Twice–5 Once–24, Twice–6 Once–25, Twice–5 0.897 Baseline characteristics No. of men/women None None None DMFT, mean (SD) Additional oral hygiene aids 3.52 (3.39) 3.67 (2.43) 3.18 (2.85) 0.759 Incipient lesions, mean (SD) 5.58 (3.48) 5.42 (4.08) 5.63 (4.64) 1.098 Abbreviations: A. nilotica, Acacia nilotica ; DMFT, decayed/missing/filled teeth; SD, standard deviation. Table 2. ANOVA results for the 3 study groups. df Mean square F value P value 21709.972 2 10854.986 0.542 1.3120 1589356.737 54 29432.532 15.825 0.0001 9.361 0.0001 Sum of squares MS (baseline) Between groups Within groups MS (Day 30) MS (Day 60) Between groups 468912.035 2 234456.017 Within groups 789459.474 54 14619.619 Between groups 389590.877 2 194795.438 Within groups 929856.000 54 17219.555 Abbreviations: df, degree of freedom; MS, mutans streptococci. Preparation of extract A water-washed section of A. nilotica bark was subjected to coarse grating (sieve No. 44) to produce a coarse powder of uniform texture. A hot solid-liquid (Kumagawa) extraction procedure was applied to obtain the extract of A. nilotica. The powder was subjected to 50% ethanol for 48 hours at 60°C-65°C. The resulting separate 50% extract was then concentrated and the ethanol solvent was completely removed under reduced pressure by a Lyotrap dryer (LTE Scientific Ltd.). The extract was stored at 4°C in a tightly closed container to preserve it from any contamination, deterioration, and/or decomposition. Inclusion and exclusion criteria Volunteers who had 1 or more active incipient lesions and/or frank carious lesions were considered to be at high risk for dental caries and were included in the study. Participants having a baseline 24 January/February 2015 plaque score >2 and a baseline DMFT index of 2-5 were included in the study. Volunteers who had used antibiotics or any mouthrinse for 7 consecutive days, or taken corticosteroids in the past 15 days were excluded from the study. Subjects with a history of sensitivity to any mouthrinse, and those who had used removable prostheses or an orthodontic appliance, were excluded from the study. All volunteers were subjected to clinical examination, and a sampling frame (n = 90) was prepared of those who fulfilled the inclusion and exclusion criteria. Subjects were instructed to refrain from any drug and alcohol consumption for the study period of 60 days and to report any consumption of these products. The subjects were divided into 3 groups (n = 30). This sample size was chosen as the minimum size required due to the calculations for error used in this study: α error <5% (P < 0.05), β error 20%, expected mean difference 3.257, and standard deviation 2.715. General Dentistry www.agd.org The volunteers were randomly allocated into 3 study groups through computergenerated numbers. Individuals were identified by code numbers throughout the study. The clinical trial was conducted according to American Dental Association’s Adjunctive Dental Therapies for the Reduction of Plaque and Gingivitis guidelines.11 All eligible subjects participated in the study. For the study, all subjects were asked to rinse with 10 ml of their designated mouthrinse BID for 30 days. Group 1 subjects were given a 50% A. nilotica mouthrinse, Group 2 subjects were given a 0.2% chlorhexidine mouthrinse, and Group 3 (control) was given a saline water mouthrinse (placebo). Methodology DMF scores and incipient lesion scores were recorded at baseline. The unstimulated salivary samples were collected from the participants and inoculated onto mitis Table 3. Post hoc significant difference test for multiple comparisons. 95% confidence interval Dependent variable Group (I) Group (J) Standard error P value Lower limit MS (baseline) A. nilotica Chlorhexidine 52.68 0.4220 -149.90 MS (Day 30) MS (Day 60) Upper limit 47.80 A. nilotica Placebo control 52.68 0.6980 -138.12 62.17 Chlorhexidine Placebo control 52.68 0.8970 -69.28 114.01 A. nilotica Chlorhexidine 33.23 0.9810 -69.23 53.23 A. nilotica Placebo control 33.23 0.0001 -212.18 -99.72 Chlorhexidine Placebo control 33.23 0.0001 -211.18 -98.72 A. nilotica Chlorhexidine 40.18 0.8560 -87.64 79.69 A. nilotica Placebo control 40.18 0.0001 -224.33 -79.99 Chlorhexidine Placebo control 40.18 0.0001 -216.85 -66.52 (I) and (J) designations according to post hoc analysis. Abbreviations: A. nilotica, Acacia nilotica ; MS, mutans streptococci. salivarius bacitracin (MSB) agar (M259, HiMedia Laboratories). The MS colony counts were obtained by a microbiologist who was blinded to the groups. Each participant was given the same brand of toothbrush and toothpaste to minimize bias. All 3 solutions were made in the university’s pharmacy department. Each mouthrinse was the same color, and kept in a coded container. Study subjects were instructed to rinse with 10 ml of mouthrinse for 60 seconds BID, post-breakfast and post-lunch, for 30 days. They were not to rinse with water afterward. They were also instructed not to consume any solid or liquid for a half hour following mouthrinse use. Except for the BID mouth rinsing, the volunteers were asked to maintain their normal oral hygiene practices. All subjects lived in the same student housing, so they all shared the same diet. A compliance diary was given to each study participant; they were asked to make an entry of each usage and side effects experienced, if any. Unstimulated saliva samples were collected and inoculated on MSB agar (MS1) before the study began (baseline). Unstimulated saliva samples were collected from subjects of all 3 groups at the end of 30 days and inoculated onto MSB agar (MS2); colony counts were obtained after 48 hours incubation. On Day 31, the subjects were instructed to stop using the mouthrinse and continue with their routine oral hygiene care. At Day 60, unstimulated saliva samples were collected again, inoculated onto MSB agar (MS3), and colony counts were obtained after incubation. Collection of saliva sample The unstimulated saliva samples were collected during the study in the mornings after the use of mouthrinse. The study subjects were asked not to swallow for 60 seconds, after which time the pooled saliva on the floor of the mouth was aspirated with a syringe. The syringes were coded and the saliva samples were diluted in distilled water. The sample was inoculated within 30 minutes after collection. All the microbiological procedures were carried out in the microbiology lab of the university’s medical college. Statistical analysis SPSS version 21 (SPSS, Inc.) was used for data analysis. Repeated ANOVA and ANOVA followed by post hoc least significant difference (LSD) tests were used for analysis. A P value of 0.05 was taken to be significant. Results All 90 participants completed the study. Descriptive statistics are presented in Table 1. No statistically significant difference was found in the baseline data between the 3 groups. Compliance with mouthrinse use was determined to be acceptable for both the experimental groups. Mean www.agd.org compliance in the A. nilotica group was 90.1% (range 87% to 95%), while that of the chlorhexidine group was 86.3% (range 82% to 96%). ANOVA was used to analyze the reduction in colony counts in the 3 groups. There was a significant decrease in the MS colony count in both the A. nilotica and chlorhexidine groups at Day 30 (85% and 83%, respectively) and at Day 60 (65% and 63%, respectively) (P < 0.0001). The colony counts obtained at Day 60 showed a slight increase compared to counts obtained at Day 30, but an overall reduction to the baseline colony count was seen (P < 0.0001). The control group showed a slight decrease at Day 30 and a slight increase at Day 60 (3% and 7%, respectively). This variation, however, was not statistically significant (P = 0.201). ANOVA was carried out to assess the intra- and intergroup variations (Table 2). There was no significant difference in the baseline colony count between the 3 groups (P = 1.312), while the difference at Day 30 and Day 60 was statistically significant (P = 0.0001). Post-hoc LSD was performed to obtain multiple comparisons (Table 3). The difference in the decrease in colony counts between A. nilotica and chlorhexidine groups was not statistically significant (P = 0.981 and P = 0.856 at Days 30 and 60, respectively). However, the differences between both Group 1 and Group 2 vs Group 3 (control) were highly significant (P < 0.0001). General Dentistry January/February 2015 25 Microbiology Investigation of antibacterial efficacy of Acacia nilotica against salivary mutans streptococci Adverse events The most common adverse event reported was a mild burning sensation in both the A. nilotica and chlorhexidine groups. The chlorhexidine group reported altered taste and brown staining of the teeth (50% and 67%, respectively). Such side effects were not recorded in the A. nilotica group. Discussion The present study was conducted to assess the antibacterial action of a 50% A. nilotica mouthrinse against salivary MS in comparison with the ‘gold standard’ 0.2% chlorhexidine mouthrinse and a placebo (saline water). Research has been focused in recent years on herbal medicines as alternatives to synthetically created antimicrobial agents, due to their wide range of biological and medicinal activities, potentially higher safety margins, and lower costs. Several antibacterial agents—such as chlorhexidine, fluorides, and various antibiotics— are commercially available that can be used to prevent dental caries. However, some of these have been reported to have undesirable side effects, including nausea, vomiting, tooth staining, and metallic taste.4 A. nilotica is considered safe for human use.12 Research on A. nilotica-containing products has demonstrated its oral health benefits. Acacia gum has the potential to inhibit early plaque formation, although there is no proven long-term benefit. For centuries, A. nilotica gum has been used for oral hygiene in the Middle East and North Africa.13 In a 2010 study, a gel containing A. nilotica significantly improved clinical gingival and plaque index scores over a period of 6 weeks.14 In a comparison study of other herbal remedies, Dhanya Kumar & Sidhu indicated that an A. nilotica extract (concentration 50%) showed the highest antimicrobial activity against S. mutans.15 Thus, a 50% extract concentration was chosen for this study. Following the use of mouthrinse for 30 days, the MS colony counts in the saliva decreased by 85% and 83% in Groups 1 and 2, respectively. This reduction was statistically significant. The MS colony counts at Day 60 showed a reduction in Groups 1 and 2 (65% and 63%, respectively). This suggests that the antibacterial efficacy of A. nilotica against salivary MS parallels that 26 January/February 2015 of chlorhexidine. In contrast, Group 3 showed a slight variation in MS colony count. For both Groups 1 and 2, there was a slight decrease in colony counts at Day 30 and a slight increase at Day 60. This variation was not statistically significant and it was possibly due to physiological changes. A. nilotica stem bark extracts contain alkaloids, saponins, cardiac glycosides, tannins, flavonoids, and anthraquinones which might be responsible for its antibacterial properties.9 A review of the available literature revealed that some authors have reported in vivo antibacterial activity of herbs such as Terminalia chebula and Triphala against salivary MS, and Aloe vera against dental plaque, but to date, no studies have been conducted to assess the effect of A. nilotica on salivary MS.16-20 The results of 50% A. nilotica extract mouthrinse on salivary MS could not be compared with other studies, as no in vivo studies that have tried to assess the same effect have been reported in the literature. However, studies have been reported that suggest that A. nilotica possesses other beneficial properties for general and oral health.21 Compliance with mouthrinse use was acceptable in both Groups 1 and 2. Mean compliance in the A. nilotica group was 93.6% while that in the chlorhexidine group was 91.2%. The taste of A. nilotica mouthrinse was acceptable to all the subjects of the group. The astringent action of A. nilotica resulted in the drying of the oral cavity, and subjects reported that it acted as a breath freshener. Side effect profiles were also checked at the end of the trial. No staining of the teeth or altered taste perception was reported by the volunteers in the A. nilotica group. Volunteers using chlorhexidine reported a yellowish discolouration of the teeth and a metallic taste. Cost effectiveness Commercially available 0.2% chlorhexidine mouthrinse (100 ml) ranges in cost from 55 to 100 rupees (or 0.90 to 1.63 USD). In India, this is very expensive for people of lower economic means. However, India’s rural population has the option to dry and powder the bark of an A. nilotica tree, and then mix it with 2 parts water to 1 part powder. This mixture can then be heated and allowed General Dentistry www.agd.org to simmer until the water is reduced by 75%. The extract can then be used as a mouthrinse. This method is the prevailing oral hygiene practice in rural parts of India. Alternatively, purified A. nilotica is commercially available in powder form. At 50 rupees (0.82 USD) for 500 g, the powder is very cost efficient and can be used instead of bark. For a family of 4, 10 mg of powder can be used to make 100 ml of mouthrinse—enough for the entire family to use for 4 days. The cost per 10 ml of mouthrinse use is estimated to be approximately 1 rupee (0.02 USD). Our data show that a mouthrinse made from A. nilotica is just as effective in combating caries as chlorhexidine. A. nilotica can be considered a viable substitute for chlorhexidine, especially among populations of lower socioeconomic means. Conclusion As S. mutans is generally considered the main oral pathogen responsible for dental caries, the fact that A. nilotica inhibited the growth of S. mutans provides some scientific rationale for the use of this plant for the treatment of dental caries. The results of the present study clearly indicate the use of A. nilotica as a viable mouthrinse among rural communities of lower economic means, where it is easily accessible. However, as this is the first attempt to assess the effects of A. nilotica on salivary S. mutans, a clinical trial of longer duration with a larger sample size is necessary in the consideration of a commercially available A. nilotica mouthrinse. Author information Dr. D. Gupta is an assistant professor, Department of Public Health Dentistry, Institute of Dental Sciences, Bareilly, Uttar Pradesh, India. Dr. R. Gupta is a principal, Government Degree College, Banbasa, Uttrakhand, India. References 1. Bagramian RA, Garcia-Godoy F, Volpe AR. The global increase in caries. A pending health crisis. Am J Dent. 2009;22(1):3-8. 2. Jones CG. Chlorhexidine: is it still the gold standard? Periodontol 2000. 1997;15:55-62. 3. McCoy LC, Wehler CJ, Rich SE, Garcia RI, Miller DR, Jones JA. Adverse events associated with chlorhexidine use: results from the Department of Veterans Affairs Dental Diabetes Study. J Am Dent Assoc. 2008; 139(2):178-183. 4. Gupta D, Bhaskar DJ, Gupta RK, et al. Effect of Terminalia chebula extract and chlorhexidine on salivary pH and periodontal health: 2 weeks randomized control trial. Phytotherapy Res. 2013;28(7):992-998. 5. Dioscorides. De Materia Medica. Available at: http:// penelope.uchicago.edu/~grout/encyclopaedia_ romana/aconite/materiamedica.html. Accessed October 1, 2014. 6. Gupta D, Gupta RK, Bhaskar DJ, et al. Comparative evaluation of Terminalia chebula extract mouthwash and chlorhexidine mouthwash on plaque and gingival inflammation - 4-week randomised control trial. Oral Health Prev Dent. 2014. [Epub ahead of print] 7. Jarvinen H, Tenevuo J, Huovinen P. Susceptibility of Streptococcus mutans to chlorohexidine and six other antimicrobial agents. Antimicrob Agents Chemother. 1993;37(5):1158-1159. 8. Dhinahar S, Lakshmi T. Role of botanicals as antimicrobial agents in management of dental infections – a review. Int J Pharm Biosci. 2011;2(4):8690-8704. 9. Deshpande SN, Kadam DG. Phytochemical analysis and antibacterial activity of Acacia nilotica against Streptococcus mutans. Int J Pharm Biosci. 2013;5(1): 236-238. 10. Xavier TF, Vijayalakshmi P. Screening of antibiotic resistant inhibitors from Indian traditional medicinal plants against Streptococcus mutans. J Plant Sci. 2007. Available at: http://www.docsdrive.com/pdfs/academicjournals/jps/2007/370-373.pdf. Accessed September 30, 2014. 11.American Dental Association Council on Scientific Affairs. Adjunctive Dental Therapies for the Reduction of Plaque and Gingivitis. Available at: http:// www.ada.org/~/media/ADA/Science%20and%20 Research/Files/guide_adjunctive.ashx. Accessed October 2, 2014. 12. Kannan N, Sakthivel KM, Guruvayoorappan C. Protective effect of Acacia nilotica (L.) against acetaminophen-induced hepatocellular damage in Wistar rats. Adv Pharmacol Sci. 2013. Available at: http://www. hindawi.com/journals/aps/2013/987692/. Accessed September 30, 2014. 13. Gazi MI. The finding of antiplaque features in Acacia arabica type of chewing gum. J Clin Periodontol. 1991; 18(1):75-77. 14. Pradeep AR, Happy D, Garg G. Short-term clinical effects of commercially available gel containing Acacia arabica: a randomized controlled clinical trial. Aust Dent J. 2010;55(1):65-69. 15. Dhanya Kumar NM, Sidhu P. The antimicrobial activity of Azardirachta Indica, Glycyrrhiza glabra, Cinnamum zeylanicum, Syzygium aromaticum, Accacia nilotica on Streptococcus mutans and Enterococcus faecalis: an in vitro study. Endodontology. 2011;23: 18-25. 16. Jagtap AG, Karkera SG. Potential of the aqueous extract of Terminalia chebula as an anticaries agent. J Ethnopharmacol. 1999;68(1-3):299-306. 17. Nayak SS, Kumar BR, Ankola AV, Hebbal M. The efficacy of Terminalia chebula rinse on Streptococcus www.agd.org mutans count in saliva and its effect on salivary pH. Oral Health Prev Dent. 2010;8(1):55-58. 18. Srinagesh J, Pushpanjali K. Assessment of antibacterial efficacy of triphala against mutans streptococci: a randomised control trial. Oral Health Prev Dent. 2011; 9(4):387-393. 19. Karim B, Bhaskar D.J., Agali C., et al. Effect of Aloe vera mouthrinse on periodontal health: triple blind randomized control trial. Oral Health Dent Manag. 2014; 13(1):14-19. 20. Gupta D, Bhaskar DJ, Gupta RK, et al. A randomized controlled clinical trial of Ocimum sanctum and chlorhexidine mouthwash on dental plaque and gingival inflammation. J Ayurveda Integr Med. 2014;5(2): 109-116. 21. Pradeep AR, Happy D, Garg G. Short-term clinical effects of commercially available gel containing Acacia arabica: a randomized controlled clinical trial. Aust Dent J. 2010;55(1):65-69. Manufacturers HiMedia Laboratories, Mumbai, India 91.22.6147.1919, www.himedialabs.com LTE Scientific Ltd., Greenfield, England 44.1457.876221, www.lte-scientifc.co.uk SPSS, Inc., Quarry Bay, Hong Kong 852.2811.9662, www.spss.com General Dentistry January/February 2015 27 Exercise No. 361 Microbiology Subject Code 013 The 15 questions for this exercise are based on the article, Investigation of antibacterial efficacy of Acacia nilotica against salivary mutans streptococci: a randomized control trial, on pages 23-27. This exercise was developed by Jean Carlson, DDS, FAGD, in association with the General Dentistry Self-Instruction committee. Reading the article and successfully completing this exercise will enable you to: •identify the physical properties of Acacia nilotica (AN); •recognize the action of AN against mutans streptococci (MS); and •understand the efficacy of chlorhexidine mouthrinses compared with AN mouthrinses. 1. Dental caries results from the interplay of all the following factors except one. Which is the exception? A.bacteria in dental plaque B. dietary carbohydrates C.physiologic age D.susceptible tooth surfaces 6. In subjects using the AN mouthrinse, the MS colony count was decreased by _____% at 30 days. A. 85 B. 83 C. 65 D. 63 2. Chlorhexidine has all of the following inherent side effects except one. Which is the exception? A. burning sensation B. altered taste C. staining of teeth D. mucosal sloughing 7. The most common adverse reaction reported was altered taste sensation in both the AN and chlorhexidine groups. Brown staining was not observed in the AN group. A. Both statements are true. B. The first statement is true; the second is false. C. The first statement is false; the second is true. D. Both statements are false. 3. An AN mouthrinse exhibits antibacterial effects against halitosisinducing bacteria on the tongue. The efficacy of AN against MS remains unproven in in vitro studies. A. Both statements are true. B. The first statement is true; the second is false. C. The first statement is false; the second is true. D. Both statements are false. 4. Volunteers in Group 1 were given _____% AN mouthrinse for use in the study. A. 40 B. 50 C. 60 D. 70 5. Study participants were instructed to rinse their mouths with ____ ml of solution for ____ seconds. A.5; 30 B. 10; 30 C. 5; 60 D. 10; 60 8. In the placebo control group, a slight variation in MS colony count was reported. There was a slight increase in colony count at 30 days with a slight decrease at 60 days. A. Both statements are true. B. The first statement is true; the second is false. C. The first statement is false; the second is true. D. Both statements are false. 9. AN stem bark extracts contain all of the following components except one. Which is the exception? A. free radicals B. tannins C. saponins D. flavonoids 10. Mean compliance of mouthrinse use in the AN group was ____%. A. 91.2 B. 93.6 C. 95.2 D. 97.6 11. Mean compliance of mouthrinse use in the chlorhexidine group was _____%. A. 81.2 B. 83.6 C. 91.2 D. 93.6 12. The cost for 100 ml 0.2% chlorhexidine mouthrinse ranges between ____ Indian rupees. A. 55-100 B. 105-150 C. 155-200 D. 205-250 13. A quantity of 500 g AN powder is priced at _____ Indian rupees. A. 20 B. 30 C. 40 D. 50 14. The average age of participants in the placebo control group was ______ years. A. 21.16 B. 21.42 C. 22.16 D. 22.74 15. The placebo group was given _______ to use as a mouthrinse. A. ethanol B. saline water C. hydrogen peroxide D. chlorhexidine Answer form is on the inside back cover. Answers for this exercise must be received by December 31, 2015. 28 January/February 2015 General Dentistry www.agd.org AGDPODCAST The AGD Podcast series features interviews with some of the profession’s most highly regarded speakers. To access, simply use your smartphone to scan each podcast’s QR code, download, and enjoy! Marketing Your Practice with Kim McQueen New Vistas in Periodontics with Sam Low, DDS, MS, MEd Insurance Coding Updates with Charles Blair, DDS Effective Web Marketing with Colin Receveur Profiting with PPO Dental Insurance with Dana Moss Embezzlement in the Dental Office with David Harris Dr. Blakeslee discusses the latest news and emerging trends with prominent dental professionals to keep you in the know. Wes Blakeslee, DMD, FAGD Diagnosis and Treatment Planning Clinical considerations for selecting implant abutments for fixed prosthodontics Roger A. Solow, DDS There is an overwhelming number of designs and components for dentists to choose from when treatment planning implant-supported restorations. The selection process can be simplified by establishing priorities on a site-by-site basis to facilitate a predictable, esthetic, and stable final result. Clinical considerations should include prosthetic support, periodontal stability, reparability, and oral hygiene, which often T reatment planning for any case that includes implant-supported restorations may involve a complex series of decisions about a multifactorial problem list. The restorative dentist, who typically finishes the case, must be able to explain to the patient why the proposed treatment is the optimal approach, and communicate to the surgeon the necessary steps for achieving the desired result. One way to organize the treatment planning is to decide on the priorities for each site and the overall goal of the comprehensive restoration. These priorities are based on the clinical considerations of prosthetic support, periodontal stability, reparability, and oral hygiene. This article discusses how these concerns influence treatment planning and the selection of implant abutments for fixed prosthodontics. Dentists must understand the relationship between implant and abutment for optimal clinical application. It is not possible to discuss all implant systems in a single article, and any mention of a specific manufacturer is intended to show a design or concept, not to make a recommendation. This article illustrates clinical decisions based on this author’s preferences, clinical experience, and the literature. Anterior and posterior tooth restorations are placed in different environments. Anterior teeth are highly visible and have a scalloped periodontium, with the facial and oral bone distinctly apical to the interproximal bone level. Posterior teeth are less visible and have flatter periodontal architecture with less disparity between the facial and oral bone and the interproximal bone levels. Anterior teeth have thin bundle bone that is lost after tooth removal, inducing significant alveolar ridge 30 January/February 2015 occur in concert. This article addresses the principles that guide implant abutment selection when treatment planning for fixed prosthodontics. Received: December 16, 2013 Revised: May 28, 2014 Accepted: September 3, 2014 alteration.1 Anterior teeth experience less masticatory and bruxing forces compared to posterior teeth.2 When using implants to restore anterior teeth, the main priority of treatment is to preserve the topography of the dentogingival interface via periodontal reconstruction and prosthetic contours for stability and esthetics. By contrast, the priority for implant restoration of posterior teeth is force management, in order to avoid damage to the implant, abutment, prosthesis, or crestal bone. However, some anterior sites are not visible due to the marginal gingiva-lip relationship or low lip activity, while some posterior sites may be quite visible due to high lip mobility, requiring tissue augmentation for acceptable esthetics. Prosthetic support and posterior tooth sites Many posterior tooth restorations have low esthetic exposure, and the priority with implant-supported restorations is to avoid adverse forces on the prosthesis and the supporting periodontium.3 Placing the implant in the center of the restorative space is the first step toward accomplishing these goals. Ridge augmentation may be necessary to create the proper dimensions for ideal implant positioning. When multiroot extraction sites are involved, immediate implant placement may be facilitated by engaging the septal bone to provide proper orientation.4,5 Placing an implant into the socket of a multirooted tooth creates a cantilevered restoration (Fig. 1). With single crowns, off-center implant placement forms a cantilever on 1 side of the implant that increases stress on the restorative material, abutment, implant, General Dentistry www.agd.org and crestal bone. In order to keep occlusal forces aligned with the long axis of the implant, the crown must be centered over the implant platform and only contact the opposing tooth during closure, not mandibular excursions. The crestal bone tolerates vertical, compressive force better than shear forces induced by lateral torque on the crown.6 The fracture of porcelain and implant components can be caused by mechanical stress related to cantilevered restorations (Fig. 2). Proper implant position in the center of the restorative space and improved prosthetic support with a wide diameter implant minimizes the cantilever problem that is most noticeable in molar sites. An average maxillary first molar is 11 mm buccolingual and 10 mm mesiodistal, while an average mandibular first molar is 10.5 mm buccolingual and 11 mm mesiodistal.7 Regular diameter Fig. 1. Implant-supported crown No. 31 with a mesial cantilever. Abutment screw loosening was attributed to magnified force by the cantilever. Fig 2. Top. Fractured fragment of implant neck due to force overload. Bottom. Distal view of crown on abutment with significant palatal horizontal cantilever. Fig. 3. Top. Soft-tissue level implant with a 6.5 mm platform for enhanced prosthetic support, centered in the edentulous space. Bottom. Regular diameter implant supporting a molar crown with large horizontal cantilever and gingival embrasures. implant platforms typically are 3.75-5 mm, while wide diameter implant platforms typically are >5 mm. A mandibular molar crown with ideal implant position and average tooth dimension would have a mesial horizontal cantilever of 3.25 mm with a 4.5 diameter platform and only 2.25 mm with a 6.5 diameter platform. Unfortunately, not all ridges are thick enough buccolingually to accommodate a wide diameter implant. A flared softtissue level implant with a 6.5 mm platform and a 4.8 mm body can be placed within a 7 mm ridge (Standard Plus WN, Straumann) (Fig. 3). The larger platform increases the linear prosthetic support by 2 mm (44% of a 4.5 mm implant) and normalizes the gingival embrasure by the same amount. This abutment is torqued into the implant with a tapered interference fit, so it is internally connected to the implant platform edge that forms the margin for the restoration, eliminating the external implant-abutment junction (IAJ) microgap.8 The wide diameter distributes force through more bone, Fig. 4. Top. Subcrestal placement of a soft-tissue level implant, complicating impressions and cement clearance. Bottom. A good restoration fit was achieved, but a nonhygienic, deep, subgingival margin persists. thus decreasing the crestal bone stress per unit area.9 The implant should be placed at the level of the gingiva or 0.5 mm intracrevicularly for esthetics, cement clearance, and patient hygiene. These design features, combined with a rough surface, minimize crestal bone loss. These implants need to be placed in the correct relationship with the rough-smooth border at the crestal bone, to prevent any vertical position errors that would require a mesostructure component or preparation of the implant platform (Fig. 4). Premolar teeth occupy a smaller space than molars and encounter less force. Providing prosthetic support is less of a priority, as the horizontal cantilever (the crown minus the crown margin dimension) is reduced. An average maxillary first premolar is 9 mm buccolingual and 7 mm mesiodistal, while an average mandibular first premolar is 7.5 mm buccolingual and 7 mm mesiodistal.7 The main concern with premolars is maintaining periodontal stability for esthetics and implant longevity. www.agd.org A regular diameter soft-tissue level implant can be used in premolar sites similar to molars. The implant must be placed accurately, as there is less margin for error in the smaller sites, and an implant malposition can result in deficient papilla size or the need to recontour adjacent teeth. A bone level implant with a platform-switch abutment is also appropriate for these sites. The platform-switch abutment has a smaller diameter compared to the implant platform that shifts the IAJ away from the bone and toward the implant center.10 The bacterial-mediated inflammatory infiltrate is displaced from the bone, preserving higher osseous levels in comparison to symmetrical abutments, where bone loss to the first implant thread is typical. Platform-switch abutments have been shown to preserve crestal bone with bone growth onto the implant shoulder.11 Reducing the 360-degree bone loss seen adjacent to symmetrical IAJs allows dentists to place the implants closer to natural teeth or implants without losing the bone General Dentistry January/February 2015 31 Diagnosis and Treatment Planning Clinical considerations for selecting implant abutments for fixed prosthodontics that supports the interproximal papilla height.12,13 The platform-switch design is indicated for all bone level abutments. In premolar implant sites, a stock titanium or zirconia abutment can be ordered after the surgeon communicates the sulcus depth (implant platform to marginal gingiva) and the restorative space (marginal gingiva to opposing tooth occlusal surface). These measurements are recorded with a periodontal probe and minimize the need for the restorative dentist to maintain a large array of components. The facial margin of the abutment should be placed 0.5 mm intracrevicularly and the oral margin should be placed at the level of the marginal gingiva to visualize complete crown seating (Fig. 5).14 If the interproximal margin is >1 mm deep, compromising thorough cement clearance, then a stock abutment with a taller gingival collar should be customized. This abutment should be seated and the gingival margins marked intraorally with a bur or ink. The abutment should be shaped extraorally with diamond burs and checked repeatedly by reseating it on the implant until the margin is correct. Alternatively, an implant level impression is obtained and the laboratory technician creates a custom abutment while a temporary abutment supports the provisional restoration. This approach involves additional time and cost, and precludes the use of the “1 abutment at 1 time” protocol. Research has shown that placement of the permanent abutment at the time of surgery helps to preserve alveolar bone levels, as repetitive detachment and attachment of titanium abutments induces minor bone loss.15,16 The dentist must be assured of the stability of the facial periodontium to place the permanent abutment at the time of surgery or healing abutment removal, since gingival recession may require abutment removal or intraoral preparation. This technique is appropriate for thick periodontal biotypes and sites where esthetics are not a concern. Laser-etched 8-12 µ channels have been shown to create an enhanced attachment of bone and connective tissue to both implants and abutments (Laser-Lok, BioHorizons IPH, Inc.).17 Connective tissue fibers inserted perpendicular to these grooves are similar to natural teeth, 32 January/February 2015 Fig. 5. Top. A premolar implant with a platformswitch abutment. Bottom. The flat gingiva permitted the use of an unaltered stock abutment. Fig. 6. Top. The dentogingival junction of the central incisors is apical to the lip during function. Bottom. The long contact ensured that the papilla filled the gingival embrasure avoiding food accumulation and air passage. instead of laying parallel as with polished titanium. This attachment was broken and reformed on detachment and replacement of healing abutments with definitive abutments.18 These microgrooves are a positive design feature to maintain crestal bone and marginal gingiva levels. If esthetics are not a concern because the dentogingival junction is hidden by an apical position beneath the lip or from an inactive lip, restoration of the implant can proceed as described above with bicuspid sites. A stock abutment can be placed and modified extraorally to create an intracrevicular margin prior to seating, impressions, and provisionalization (Fig. 6). In most situations, anterior implantsupported restorations are placed in highly visible areas where both white and pink esthetics are apparent. Forces in the anterior region are low, and the disparity between crown dimension and prosthetic support is small. The priority in anterior site restoration is periodontal tissue stability and esthetics. The restorative dentist must create a prosthetic contour—from the orally positioned implant platform to the incisal edge—that molds the gingiva into the correct position and replicates natural tooth esthetics. Platform-switch bone level implants are recommended in anterior esthetic sites to preserve crestal bone and give the restorative dentist control over the entire prosthetic contour. The restorative margin position for tissue level implants is determined by the surgeon and leaves little room for adjustment if the position is not correct. In ideal Periodontal stability and anterior tooth sites Tomographic studies show that the buccal plate of bone adjacent to anterior teeth is often <1 mm thick or absent entirely, which results in dehiscence and fenestrations.19,20 This bone is categorized as bundle bone, a hybrid of osseous and fibrous tissues. During root extraction, this bone is resorbed after the periodontal ligament ruptures.21 This loss of the socket wall subsequently deforms the residual alveolar ridge and complicates placement of anterior implants. Implants placed in the center of the resorbed ridge will be toward the oral side of the original tooth position. Intentional placement of the implant further toward the oral side will maximize buccal bone dimension. Most anterior implant-supported restorations require tissue augmentation to restore the topography of the periodontium and achieve stable esthetics.22 General Dentistry www.agd.org A B C D Fig. 7. A. One-piece implant with good mesiodistal placement and 2 mm of titanium from the restorative margin to the bone crest. B. Provisional restoration with healthy tissue but asymmetric length with tooth No. 10. C. Gingival sculpting with retraction cord and electrosurgery to elongate the facial length of the restoration. D. All-porcelain restoration with a facial and apical emergence profile. circumstances, the biologic width of the prosthetically molded and supported gingiva is allowed to mature for 3-6 months; at that point, its contours are recorded immediately after the provisional restoration is removed.23,24 A cement-retained provisional on a permanent abutment can be used for anterior restorations with the “1 abutment at 1 time” protocol, if the abutment properly supports the facial tissue and a 0.5 mm intracrevicular margin is present for cement clearance. In this scenario, only interproximal tissue modification would be necessary, as pressure from the provisional contour could improve papillae shape. However, in most anterior site cases, the need to modify the facial contour sequentially, alter a permanent abutment margin intraorally, remove the cement completely, or avoid cement deterioration/re-cementation during the maturation period make screw-retained provisionals more practical.25,26 Screwretained provisional restorations facilitate tissue molding for papillae and pontic sites by maintaining constant gentle pressure, inducing gingival blanching that dissipates within 10 minutes.25,26 Anterior tooth restoration using an abutment and crown versus a screw-retained crown is determined by the position and angulation of the implant. A screw-retained crown that attaches directly to the implant platform requires the implant to be orally positioned so that the screw access channel exits through the cingulum of the crown. When the implant is more facially positioned the abutment acts as a mesostructure to correct the position or angulation that would result in the screw access channel exiting at, or facial to the incisal edge. A conventional crown can be cemented on the properly aligned abutment. Custom abutments allow dentists to control the cervical dimension and margin location. They are indicated to either eliminate the access defect of screw retention or compensate for the vertical and horizontal implant position. A circumferential 0.5 mm intracrevicular margin creates good esthetics with predictable cement removal. The most coronal subgingival aspect of a custom abutment or a screw-retained crown has the greatest influence on the gingival support and level.27 For predictable pink esthetics, the facial gingival thickness should be 3 mm; at this thickness, abutment color is not an issue.28 A 2007 in vitro study by Jung et al reported that titanium perceptibly altered abutment color when gingival thickness was 2 mm but not when it was 3 mm, while white zirconia did not alter color for either thickness.29 More recently, Happe et al found that titanium induced a visible change in gingival 1.5 mm thick while white or dyed zirconia did not.30 A zirconia abutment should be considered when the www.agd.org facial gingiva is less than 3 mm thick or has a thin biotype where a periodontal probe is visible when introduced into the sulcus. A 2009 systematic review showed that zirconia abutments met or exceeded the performance of titanium abutments in terms of survivability and technical complications.31 One-piece implants are indicated for anterior sites with a restricted mesiodistal dimension. The small cervical width of the implant would be reduced and weakened if a screw channel was used to attach an abutment. This system has no IAJ or micromobility; however, the surgeon must place the implant precisely in 3 dimensions for an optimal restoration. The restorative dentist can customize the coronal aspect of the implant, but cannot substitute another abutment (in case of over-reduction) or compensate for problems with vertical position by using a different abutment collar or switching to a screw-retained crown (Fig. 7). Reparability of cement vs screw retention Historically, a high incidence of abutment screw loosening and the need to access and retorque them favored screw retention for fixed prostheses.32,33 According to a 2008 study by Theoharidu et al, abutment screw loosening occurs in approximately 2.5% of single implant restorations when proper antirotational features and torque are General Dentistry January/February 2015 33 Diagnosis and Treatment Planning Clinical considerations for selecting implant abutments for fixed prosthodontics used.34 The decision to use cement or screw retention is based on the need to contour periodontal tissues, interocclusal space, subgingival implant platform location, or anticipated need to repair a prosthesis. Limited interocclusal space (<5 mm) makes cement retention difficult. Restorative material 2 mm thick would leave an abutment height of only 3 mm for frictional crown retention. In such cases, screw-retained crowns are recommended, as inadequate abutment height compromises the ability of cementretained restorations to resist dislodgement, especially in posterior tooth sites.35 Cement retention permits the same clinical protocol as restorative dentistry on natural teeth. Cement may act as a stressbreaker for splinted crowns and bridges, with no occlusal access restorations to compromise esthetics or occlusal contacts. When necessary, crown retrieval can be performed via occlusal access to create a screw-retained design. It is crucial to avoid excessive provisional or permanent cement in the sulcus, which could cause peri-implantitis. The following protocol is the same for both provisional and permanent cements. The axial wall of the abutment is roughened with a diamond bur, or a slot undercut is placed in the gingival third of the axial wall to resist crown decementation due to smoothwalled abutments. Next, retraction cord is placed in the sulcus. A slightly undersized die, to create cement space, is fabricated from the intaglio of the crown with a fastset polyvinyl siloxane (PVS) (Blu-Mousse, Parkell, Inc.).36 A thin, slow-setting layer of cement is placed inside the crown and the crown is seated on the PVS die to remove excess. The crown is then seated on the abutment and removed. The cord and any excess cement are removed and the crown is immediately reseated. This technique minimizes cement excess and avoids cord entrapment under crowns. A moderately strong provisional cement (IRM, DENTSPLY Caulk) can retain a relined provisional crown with a precise fit for several months. Zinc phospate cement is used for permanent cementation since it is radiopaque and water soluble. Radiotransparent, water insoluble, resin cement should not be used for implantsupported crowns since it is the most difficult type to detect and remove should 34 January/February 2015 any excess polymerize past the margin.37 Residual cement removal is increasingly difficult with deeper subgingival margins, and this excess cement is directly related to peri-implantitis. Screw retention avoids this problem and is indicated for patients with deep subgingival margins.38 Bruxers and patients who consume hard or abrasive foods may experience a higher incidence of repair. The anticipated need for future repairs may be determined by a patient’s history of repeated restoration, noncompliance with occlusal splint therapy, or damage to high quality provisional restorations. Large cases with multiple, splinted, implant-supported crowns or multiple-abutment implantsupported bridges may be more difficult to repair. In these cases, damage to 1 area could require accessing and disassembling the cemented structure or the fabrication of an overcasting. Screw retention facilitates removing the entire structure and replacing it with a screw-retained provisional restoration during laboratory repair. Repair may also be necessary in the provisional phase of restoration. Screw retention is recommended in cases of long-term provisionalization, when removal of the prosthesis is needed for specialist procedures, or for patients who risk decementation while traveling. Multi-unit abutments are titanium components that compensate for soft tissue thickness and implant angulation problems relative to the occlusal surfaces of a screw-retained prosthesis. They function as a mesostructure that allows the prosthesis to seat at the abutment level instead of the implant platform level, with screw retention channels at favorable locations through the occlusal surfaces Oral hygiene and prosthesis design Oral hygiene requirements influence prosthesis design, with regard to access for routine frictional cleaning, minimizing food entrapment in the gingival embrasure, and creating optimal interproximal contacts. Over-contoured implant-supported crowns inhibit access for proper hygiene, resulting in plaque accumulation that may lead to peri-implantitis.39 A proper gingival embrasure form is just as important for implant restorations as it is with orthodontic repositioning or the restoration of General Dentistry www.agd.org Fig. 8. Top. Parallel placement of implant determined by the surgical guide derived from a diagnostic wax-up. Bottom. Individual gold castings on implants No. 29 and 30, and tooth No. 31. natural teeth for predictable maintenance. Cantilevered restorations can create gingival embrasures that trap food and may compromise the ability to maintain hygiene on the adjacent tooth (Fig. 1).40 Posterior crowns on contiguous implants can be restored as nonsplinted single units that have the same longevity as splinted restorations.41,42 However, adjusting the interproximal contacts can be a challenge since the ankylosed implant does not move. The resilient periodontal ligament of a natural tooth allows for a slight separation of the interproximal contact. The contacts must be adjusted to allow thin floss to pass without creating an open contact that collects food. This adjustment involves marking the interproximal contact repeatedly by seating the crown (with marking ribbon between it and the adjacent tooth) and polishing the marked area. This treatment allows patients to brush and floss normally; however, it requires a normal gingival embrasure dimension to create an ideal contact area (approximately 3 x 2 mm) with the papilla, which fills the embrasure and precludes lateral food impaction (Fig. 8). If proper contacts cannot be developed, the crowns should be splinted to avoid food entrapment. this process by analyzing the problem list and designating priorities for each implant site that support the total restorative plan. Author information Dr. Solow is in private practice in Mill Valley, California, and a visiting faculty member at the Pankey Institute, Key Biscayne, Florida. References Fig. 9. Top. Four posterior tooth implants supporting a cemented, splinted prosthesis. The pronounced interproximal contacts normalize the gingival embrasures. Bottom. Provisional restoration with a large crown-to-implant ratio, large interproximal contacts, and normal gingival embrasures. Implants often are placed after traumatic tooth loss or advanced periodontal disease that results in significant bone loss and a large restorative space (Fig. 9). When these contiguous implants are restored, they should be splinted together to bring the restorative contours in contact with the gingival tissue and avoid exaggerated gingival embrasures and food entrapment. Nonsplinted crowns would either require perfecting large contact areas with normal gingival embrasures or accept the normal contact areas with open gingival embrasures that can trap food. Summary Treatment planning for implant-supported restorations requires a thorough understanding of the periodontal requirements for a stable and esthetic foundation. Choices for the abutment and the implantabutment interface should be based on the anatomy and the clinical considerations of each particular site. Dentists can simplify 1. Nevins M, Camelo M, De Paoli S, et al. A study of the fate of the buccal wall of extraction sockets of teeth with prominent roots. Int J Periodontics Restorative Dent. 2006;26(1):19-29. 2. Kumagi H, Suzuki T, Hamada T, Sondang P, Fujitani M, Nikawa H. Occlusal force distribution on the dental arch during various levels of clenching. J Oral Rehabil. 1999;26(12):932-935. 3. Crispin BJ, Watson JF. Margin placement of esthetic veneer crown. Part II: posterior tooth visibility. J Prosthet Dent. 1981;45(4):389-391. 4. Fugazzotto PA. Implant placement at the time of mandibular molar extraction: description of technique and preliminary results of 341 cases. J Periodontol. 2008; 79(4):737-747. 5. Fugazzotto PA. Implant placement at the time of maxillary molar extraction: treatment protocols and report of results. J Periodontol. 2008;79(2):216-223. 6. Kim Y, Oh TJ, Misch CE, Wang HL. Occlusal considerations in implant therapy: clinical guidelines with biomechanical rationale. Clin Oral Implants Res. 2005; 16(1):26-35. 7. Kraus BS, Jordan RE, Abrams L. Dental Anatomy and Occlusion. Baltimore, MD: Williams and Wilkins Co.; 1973:48-94. 8. Bozkaya D, Muftu S. Mechanics of the tapered interference fit in dental implants. J Biomech. 2003;36(11): 1649-1658. 9. Anitua E, Tapia R, Luzuriaga F, Orive G. Influence of implant length, diameter, and geometry on stress distribution: a finite element analysis. Int J Periodontics Restorative Dent. 2010;30(1):89-95. 10. Lazzara RJ, Porter SS. Platform switching: a new concept in implant dentistry for controlling postrestorative crestal bone levels. Int J Periodontics Restorative Dent. 2006;26(1):9-17. 11. Degidi M, Perrotti V, Shibli JA, Novaes AB, Piattelli A, Iezzi G. Equicrestal and subcrestal dental implants: a histologic and histomorphometric evaluation of nine retrieved human implants. J Periodontol. 2011;82(5): 708-715. 12. Vela X, Mendez V, Rodriguez X, Segala M, Tarnow DP. Crestal bone changes on platform-switched implants and adjacent teeth when the tooth-implant distance is less than 1.5 mm. Int J Periodontics Restorative Dent. 2012;32(2):149-155. 13. Nevins M, Nevins ML, Gobbato L, Lee HJ, Wang CW, Kim DM. Maintaining interimplant crestal bone height via a combined platform-switched, Laser-Lok implant/ abutment system: a proof-of-principle canine study. Int J Periodontics Restorative Dent. 2013;33(3):261-267. 14. Nevins M, Skurow HM. The intracrevicular restorative margin, the biologic width, and the maintenance of the gingival margin. Int J Periodontics Restorative Dent. 1984;4(3):30-49. www.agd.org 15. Degidi M, Nardi D, Piattelli A. One abutment at one time: non-removal of an immediate abutment and its effect on bone healing around subcrestal tapered implants. Clin Oral Implants Res. 2011;22(11):13031307. 16. Abrahamsson I, Berglundh T, Lindhe J. The mucosal barrier following abutment dis/reconnection. An experimental study in dogs. 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Int J Periodontics Restorative Dent. 2008;28(5): 469-477. 22. Buser D, Halbritter S, Hart C, et al. Early implant placement with simultaneous guided bone regeneration following single-tooth extraction in the esthetic zone: 12-month results of a prospective study with 20 consecutive patients. J Periodontol. 2009;80(1):152-162. 23. Wilson RD, Maynard G. Intracrevicular restorative dentistry. Int J Periodontics Restorative Dent. 1981;1(4): 34-49. 24. Priest G. Developing optimal tissue profiles implantlevel provisional restorations. Dent Today. 2005; 24(11):96, 98, 100. 25. Potashnick SR. Soft tissue modeling for the esthetic single-tooth implant restoration. J Esthet Dent. 1998; 10(3):121-131. 26. Issarayangkul C, Schoenbaum TR, McLaren EA. Prosthetic soft tissue management following two periimplant graft failures: a clinical report. J Prosthet Dent. 2013;110(3):155-160. 27.Su H, Gonzalez-Martin O, Weisgold A, Lee E. Considerations of implant abutment and contour: critical contour and subcritical contour. Int J Periodontics Restorative Dent. 2010;30(4):335-343. 28. Gamborena I, Blatz MB. The gray zone around dental implants: keys to esthetic success. Am J Esthet Dent. 2011;1(1):26-46. 29. Jung RE, Sailer I, Hammerle CH, Attin T, Schmidlin P. In vitro color changes of soft tissues caused by restorative materials. Int J Periodontics Restorative Dent. 2007;27(3):251-257. 30. Happe A, Schulte-Mattler V, Strassert C, et al. In vitro color changes of soft tissues caused by dyed fluorescent zirconia and nondyed, nonfluorescent zirconia in thin mucosa. Int J Periodontics Restorative Dent. 2013; 33(1):e1-e8. 31. Sailer I, Philipp A, Zembic A, Pjetursson BE, Hammerle CH, Zwahlen M. A systematic review of the performance of ceramic and metal implant abutments General Dentistry January/February 2015 35 Diagnosis and Treatment Planning Clinical considerations for selecting implant abutments for fixed prosthodontics supporting fixed implant reconstructions. Clin Oral Implants Res. 2009;20(Suppl 4):4-31. 32. Becker W, Becker BE. Replacement of maxillary and mandibular molars with single endosseous implant restorations: a retrospective study. J Prosthet Dent. 1995;74(1):51-55. 33. Kallus T, Bessing C. Loose gold screws frequently occur in full-arch fixed prostheses supported by osseointegrated implants after 5 years. Int J Oral Maxillofac Implants. 1994;9(2):169-178. 34. Theoharidu A, Petridis HP, Tazannas K, Garefis P. Abutment screw loosening in single-implant restorations: a systematic review. Int J Oral Maxillofac Implants. 2008;23(4):681-690. 35. Taylor TD, Belser U, Mericske-Stern R. Prosthodontic considerations. Clin Oral Implants Res. 2000; 11(Suppl 1):101-107. 36. Wadhwani C, Pineyro A. Technique for controlling the cement for an implant crown. J Prosthet Dent. 2009; 102(1):57-58. 37. Wadhwani C, Hess T, Faber T, Pineyro A, Chen CS. A descriptive study of the radiographic density of implant restorative cements. J Prosthet Dent. 2010; 103(5):295-302. 38. Wilson TG Jr. The positive relationship between excess cement and peri-implant disease: a prospective clinical endoscopic study. J Periodontol. 2009;80(9):1388-1392. 39. Chaves ES, Lovell JS, Tahmasebi S. Implant-supported crown design and the risk for peri-implantitis. Clin Adv Periodont. 2014;4(2):118-126. 40. Chiche G. Pinault A. Considerations for fabrication of implant-supported posterior restorations. Int J Prosthodont.1991;4(1):37-44. 41. Simon RL. Single implant-supported molar and premolar crowns: a ten-year retrospective clinical report. J Prosthet Dent. 2003;90(6):517-521. 42. Mendonca JA, Francischone CE, Senna PM, Matos de Oliveira AE, Sotto-Maior BS. A retrospective evaluation of the survival rates of splinted and non-splinted short dental implants in posterior partially edentulous jaws. J Periodontol. 2014;85(6):787-794. Manufacturers BioHorizons IPH, Inc., Birmingham, AL 888.246.8338, www.biohorizons.com DENTSPLY Caulk, Milford, DE 800.532.2855, www,caulk.com Parkell, Inc., Edgewood, NY 800.243.7446, www.parkell.com Straumann, Andover, MA 978.747.2500, www.straumann.com There are more articles on DIAGNOSIS AND TREATMENT PLANNING in the online edition. •Central giant cell lesion: diagnosis to rehabilitation •Alveolar ridge splitting for implant placement: a review of the procedure and report of 3 cases •Atypical presentation of salivary mucocele: diagnosis and management Visit www.agd.org/GeneralDentistry 36 January/February 2015 General Dentistry www.agd.org Dental Materials Surgical repair of invasive cervical root resorption with calcium-enriched mixture cement: a case report Saeed Asgary, DDS, MS n Mahta Fazlyab, DDS, MS Invasive cervical resorption (ICR) occurs in the cervical area of the teeth due to the formation of a soft tissue that progressively resorbs dentin. The disease is asymptomatic unless the pulp is exposed. This article presents a case involving a mandibular canine that was treated with a calcium-enriched mixture (CEM) cement. After a full mucoperiosteal flap was performed, the soft tissue was curetted away and the cavity filled with CEM biomaterial. One week later, the supragingival surface of the CEM was polished and covered with composite resin. At a 1-year followup visit, the pulp was healthy and the gingival probing depth decreased I rritation of the periodontal ligament or pulp can lead to internal or external resorption.1 Invasive cervical resorption (ICR) refers to a type of external root resorption, defined as a resorptive process in the cervical area that involves the root surface in the junctional epithelium zone.2,3 Other terms used to describe this process include odontoclastoma, peripheral cervical resorption, extracanal invasive resorption, supraosseous extracanal invasive resorption, and subepithelial external root resorption.3,4 The term invasive describes the aggressive nature of this lesion.3,5,6 Although early diagnosis may be difficult, some clinical signs can indicate the presence of an ICR lesion, such as a pinkish hue in the crown (as a result of the thinning resorbed dentin), the translucency of enamel that makes the vascular resorptive tissue visible, and contour irregularities.3,7-10 The condition usually is painless due to a predentin layer that protects the pulp.4,7,11-14 Symptoms develop when the resorption penetrates through this barrier and the pulp is invaded secondarily by oral bacteria.11,13 Most lesions seen on periapical radiographs are poorly defined with irregular borders, with what has been referred to as a “moth-eaten” appearance.1,5,14 The outline of the root canal can be seen as a radiopaque line through the lesion.1,5,14 The etiology of ICR is poorly understood; however, it has been suggested that a type of fibrovascular tissue and clastic resorbing cells may be responsible.3,4,10,15 Direct contact between the dentin and from >3 mm to 1 mm, showing attachment gain. As a biocompatible material, CEM has proven its ability in dentinogenesis, cementogenesis, and osteogenesis; it may prove to be a suitable biomaterial for treating ICR cases. Received: June 6, 2013 Accepted: September 3, 2013 Key words: calcium-enriched mixture, CEM cement, cervical resorption, endodontic, invasive cervical root resorption the periodontium (due to a defect in the cementum layer) is necessary for such an invasion.3-5,10,16 Several potential predisposing factors have been identified, including trauma, orthodontic treatment, dentoalveolar surgery, and periodontal treatment; in addition, feline herpes virus type 1 is suspected as an etiologic cofactor.5,17 Heithersay developed a clinical classification system for such lesions: Class 1, a small lesion near the cervical area with shallow penetration into the dentine; Class 2, a well-defined lesion that has penetrated close to the coronal pulp with little or no extension into the radicular dentine; Class 3, a deeper invasion of dentine that not only involves the coronal dentine but also extends into the coronal third of the root (the majority of patients present at this stage); and Class 4, a large resorptive process that extends beyond the coronal third of the root.5 The author also recommended that dentists only treat defects categorized as Class 1, 2, or 3, as the extensive nature of Class 4 lesions makes treatment difficult.5,18,19 The basic goal of ICR treatment is the inactivation of all resorbing tissue and the reconstitution of the tooth structure so that the tooth may be retained for health and esthetics.9-11,15 In a 2004 article, Heithersay recommended a treatment regimen that included mechanical/chemical debridement of the resorptive lesions, followed by restoration.6 That same article also offered a nonsurgical technique involving a 90% aqueous solution of trichloracetic acid applied topically to the resorptive www.agd.org tissue, followed by curettage, and—when necessary—endodontic treatment.6 The defect can be restored using glass ionomer cement, resin-modified glass ionomer, or mineral trioxide aggregate (MTA).3,6,19-23 The material needs to be placed close to the pulp; thus, it must be nontoxic and biocompatible, provide a perfect seal to prevent leakage of environmental irritants through the cavity walls, induce dentinogenesis, demonstrate antibacterial behavior, and cause minimal pulp inflammation.24 The selected treatment must also provide an appropriate environment for osteogenesis and cementogenesis, which is followed by soft tissue attachment gain.23 Recently, a new endodontic cement composed of a calcium-enriched mixture (CEM) was introduced.25 It has the same clinical indications as MTA but a different chemical formulation.25 CEM cement is biocompatible, nontoxic, and antibacterial, while also providing a good seal.8,24,25 CEM material is hard tissue inductive, dentinogenic, cementogenic, and osteogenic—properties that make CEM an appropriate biomaterial for treating ICR.26 This article presents a case in which CEM cement was used to treat a Class 3 ICR in a mandibular canine. Case report A man in his early thirties had the chief complaint of a carious-like lesion on his mandibular left canine. A brief examination of the dental and gingival tissues revealed that the patient had normal hygiene and no carious lesions, General Dentistry January/February 2015 37 Dental Materials Surgical repair of invasive cervical root resorption with calcium-enriched mixture cement: a case report Fig. 1. A photograph of a periodontal probe assessing the lesion depth of the patient’s left mandibular canine. Fig. 2. A radiograph of the lesion in the affected tooth. Note the motheaten margins and lesion extending beyond the crestal bone. Fig. 3. Local anesthesia is injected into the soft tissue prior to flap resection. Fig. 5. The cavity is filled with calciumenriched mixture (CEM) cement prior to flap replacement. Fig. 6. A radiograph taken of the tooth after the CEM cement restoration was placed. Fig. 7. Histological views of the soft tissue specimen (H&E). A. Granulation tissue with chronic inflammatory cell infiltrate (magnification 100X). B. Same view at higher magnification (400X). Note the dense collagen matrix and lymphocytic infiltration. although he had some amalgam restorations on his molars and premolars. His most recent dental visit had taken place 7 months earlier. A cavity was visible on the buccal cervical area of the mandibular left canine; the contour was irregular and extended apically beyond the gingival margin (Fig. 1). An explorer revealed the tissue that filled the defect was extremely hyperemic and the dentin beyond the tissue on the pulpal side appeared stiff and sound. The probing depth on the midbuccal area was >3 mm. Orthoradial periapical radiographs showed a radiolucent lesion on the cervical area. The margins had a moth-eaten pattern, and the most apical margin had extended 38 January/February 2015 beneath the bone crest. The root canal could be seen through the radiolucency (Fig. 2). The patient did not report any sensitivity to cold or heat, and vitality pulp testing revealed normal responses compared to the mandibular right canine. Given the nature of the lesion, a diagnosis of ICR was made. After an antibacterial mouth rinse, local anesthesia was injected into the resorptive soft tissue (Fig. 3), and an intrasulcular full thickness flap was raised to disclose the margin of the lesion. Crestal bone had recessed to the most apical margin of the cavity. The resorptive tissue that replaced the dentin was curetted by using an excavator; in addition, all granulated General Dentistry www.agd.org Fig. 4. A full mucoperiosteal flap is resected and the soft tissue is curetted away. Note the absence of pulp exposure and the irregularity of the margins. tissue was removed from the inner side of the flap. The cavity was evacuated without any exposure of the pulp space (Fig. 4). CEM cement powder and liquid (BioniqueDent) were mixed according to the manufacturer’s instructions, and placed into the cavity until it was filled completely (Fig. 5). Another radiograph was taken to confirm the quality of the CEM restoration (Fig. 6). The flap was sutured and the patient was given postoperative instructions. The patient made a follow-up appointment to remove the sutures 1 week postsurgery. The curetted soft tissue was placed in a 10% formalin solution for common histological evaluation with H&E staining (Fig. 7). Fig. 8. An anterior view of the treated tooth 7 days postsurgery. Fig. 12. The tooth at a 1-year followup, with a gingival depth of 1 mm. Fig. 9. An anterior view of the tooth 10 days post-treatment. Note the supragingival portion of the CEM cement is polished. Fig. 10. The tooth 10 days posttreatment, after the surface was covered with flowable composite resin. Fig. 13. A radiograph of the tooth taken at the 1-year follow-up visit. Examination of the tissue showed a chronic infiltration with lymphocytes dominating in a dense collagen matrix. The CEM filling was tested clinically at the follow-up appointment.27 The filling remained intact, except for some stains and debris covering the surface (due to the porous surface of the material) (Fig. 8). Ten days postsurgery, the patient returned for the next treatment step. The surface of the CEM cement was polished to make a clean surface (Fig. 9). After etching and placement of the bonding resin (Margin Bond, Coltene/Whaledent, Inc.), the supragingival portion of the cavity was filled with composite (Synergy Nano Formula, Coltene/Whaledent, Inc.) (Fig. 10). Figures 11 and 12 show the patient at 3 months and 1 year, respectively. At the 1-year follow-up, the probing depth on the midbuccal area was 1 mm. A radiograph taken at that follow-up visit showed that the tooth had remained completely asymptomatic with normal periradicular and periapical tissues (Fig. 13). During all the scheduled follow-up visits, the patient reported no problems with this tooth, and vitality testing confirmed the pulp’s normal condition. Discussion An ICR in a mandibular canine was exposed surgically and treated successfully with CEM cement with no endodontic co-intervention. In the present case, the contributing factor to cervical resorption www.agd.org Fig. 11. The tooth at a 3-month follow-up. Note the healthy gingival tissues. remains unknown. The present case was a Heithersay Class 3 type.6 Without treatment, the resorption would have proceeded progressively, involving the dental pulp or causing cervical fracture of the tooth.6 The patient had no signs or symptoms; the color of his tooth led him to seek treatment. Subgingival caries was listed in the differential diagnosis. These have a “sticky feeling” on probing in cases of ICR. By contrast, the remaining hard dentin on the pulpal side made a scraping sound on probing. In the present case, the dentin overlying the pulp was completely sound and stiff. According to Patel et al, the radiolucent band across the entire neck of the tooth on periapical radiographs (known as the cervical burnout) needs to be ruled out as well.3 Recently, cone beam computed tomography (CBCT) has been used to assess the position and the true extent of ICR lesions.13,21 However, CBCT is a costly and time-consuming diagnostic tool, and it was determined that the clinical and radiographic examinations taken in the present case revealed sufficient information about the lesion. As mentioned previously, histological assessment of the lesion revealed a chronic infiltration with lymphocytes dominating in a dense collagen matrix, which is how granulomatous tissue appears, and is the common histological finding in ICR cases.3 Early defects usually do not contain acute inflammatory cells, which suggests a General Dentistry January/February 2015 39 Dental Materials Surgical repair of invasive cervical root resorption with calcium-enriched mixture cement: a case report nonbacterial etiology.3 However, it is possible that a secondary bacterial colonization of dentinal tubules at a later stage might induce an acute inflammatory response. Treatment regimens for ICR include debridement of the resorptive lesions followed by restoration.5,6,18,19 In the present case, the granulated tissue was curetted completely after flap reflection. The proposed nonsurgical treatment plan by Heithersay & Wilson, which uses 90% trichloracetic acid, was rejected in this case, as the authors believe that there would be a risk of incomplete tissue removal and restoration of the cavity, due to the apical extension of the defect.19 According to Patel et al, treating ICR and decreasing the chance of recurrence requires reflecting a full-thickness periosteal flap, curetting away the granulation tissue, and severing the blood supply to the resorbing cells.3 The surgical technique used in the present case eliminated the chance that trichloracetic acid (a cytotoxic material) would get close to the vital pulp. The drawbacks of MTA—including its high cost, long setting time, difficult handling properties, limited antibacterial effects against some endodontic pathogens, and potential for discoloration—prevent it from being an ideal biomaterial for treating ICR in anterior teeth.22,23 CEM cement and MTA have similar clinical uses; however, the water-based CEM cement offers a shorter setting time, increased flow, and decreased film thickness.26 In addition, CEM cement has the ability to release indigenous calcium and phosphorus ions to form hydroxyapatite, which ensures an effective bioseal after setting—a prerequisite for any biomaterial used in proximity to pulp.24 In the present case, the cavity was restored with CEM cement; at a follow-up visit, the CEM cement bulk was polished to remove the stains and leave a flat white surface. Next, the supragingival part of the CEM cement was covered with a composite restoration for esthetics. CEM cement can induce cementogenesis and this cementum layer acts as a biologic barrier.26 In the present case, a 2 mm reduction in probing depth revealed the attachment gain, offering additional proof of CEM cement’s potential. CEM cement had higher antimicrobial activity, and caused less inflammation (although not 40 January/February 2015 significantly different) when compared to MTA.26 Advantages of this study’s treatment plan include biocompatibility, induction of dentinogenesis, cementogenesis, and perfect seal. CEM cement offers a high alkalinity, which can be a mechanism of osteoclast inactivation; it also did not result in tooth discoloration, a drawback of MTA.26,28 Conclusion Given the biological properties of CEM cement, it may be an appropriate biomaterial in cases of ICR. Further research is recommended concerning the mechanisms by which CEM cement stimulates regeneration and interferes with periodontal ligament inflammation. Author information Dr. Asgary is a professor and dean, Iranian Center for Endodontic Research, Research Institute of Dental Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran, where Dr. Fazlyab is an endodontist, Dental Research Center. References 1. Ne RF, Witherspoon DE, Gutmann JL. Tooth resorption. Quintessence Int. 1999;30(1):9-25. 2. Vinothkumar TS, Tamilselvi R, Kandaswamy D. Reverse sandwich restoration for the management of invasive cervical resorption: a case report. J Endod. 2011;37(5): 706-710. 3. Patel S, Kanagasingam S, Pitt Ford T. External cervical resorption: a review. J Endod. 2009;35(5):616-625. 4. Thonen A, Peltomaki T, Patcas R, Zehnder M. Occurrence of cervical invasive root resorption in first and second molar teeth of orthodontic patients eight years after bracket removal. J Endod. 2013;39(1):27-30. 5. Heithersay GS. Invasive cervical resorption: an analysis of potential predisposing factors. Quintessence Int. 1999;30(2):83-95. 6. Heithersay GS. Invasive cervical resorption. Endod Topics. 2004;7(1):73-92. 7. Silveira LF, Silveira CF, Martos J, Piovesan EM, Cesar Neto JB. Clinical technique for invasive cervical root resorption. J Conserv Dent. 2011;14(4):440-444. 8. Asgary S, Ahmadyar M. One-visit endodontic retreatment of combined external/internal root resorption using a calcium-enriched mixture. Gen Dent. 2012; 60(4):e244-e248. 9. Kim Y, Lee CY, Kim E, Roh BD. Invasive cervical resorption: treatment challenges. Restor Dent Endod. 2012; 37(4):228-231. 10. Fuss Z, Tsesis I, Lin S. Root resorption—diagnosis, classification and treatment choices based on stimulation factors. Dent Traumatol. 2003;19(4):175-182. 11. Smidt A, Nuni E, Keinan D. Invasive cervical root resorption: treatment rationale with an interdisciplinary approach. J Endod. 2007;33(11):1383-1387. 12. Mattar R, Pereira SA, Rodor RC, Rodrigues DB. External multiple invasive cervical resorption with General Dentistry www.agd.org subsequent arrest of the resorption. Dent Traumatol. 2008; 24(5):556-559. 13. Gunst V, Mavridou A, Huybrechts B, Van Gorp G, Bergmans L, Lambrechts P. External cervical resorption: an analysis using cone beam and microfocus computed tomography and scanning electron microscopy. Int Endod J. 2013;46(9):877-887. 14. Trope M. Cervical root resorption. J Am Dent Assoc. 1997;128(Suppl):56S-59S. 15. Yu VS, Messer HH, Tan KB. Multiple idiopathic cervical resorption: case report and discussion of management options. Int Endod J. 2011;44(1):77-85. 16. Lin YP, Love RM, Friedlander LT, Shang HF, Pai MH. Expression of Toll-like receptors 2 and 4 and the OPG-RANKL-RANK system in inflammatory external root resorption and external cervical resorption. Int Endod J. 2013;46(10):971-981. 17. von Arx T, Schawalder P, Ackermann M, Bosshardt DD. Human and feline invasive cervical resorptions: the missing link?—Presentation of four cases. J Endod. 2009;35(6):904-913. 18. Heithersay GS, Dahlstrom SW, Marin PD. Incidence of invasive cervical resorption in bleached root-filled teeth. Aust Dent J. 1994;39(2):82-87. 19. Heithersay GS, Wilson DF. Tissue responses in the rat to trichloracetic acid—an agent used in the treatment of invasive cervical resorption. Aust Dent J. 1988; 33(6):451-461. 20. Hiremath H, Yakub SS, Metgud S, Bhagwat SV, Kulkarni S. Invasive cervical resorption: a case report. J Endod. 2007;33(8):999-1003. 21. Estevez R, Aranguren J, Escorial A, et al. Invasive cervical resorption Class III in a maxillary central incisor: diagnosis and follow-up by means of cone-beam computed tomography. J Endod. 2010;36(12):2012-2014. 22. Park JB, Lee JH. Use of mineral trioxide aggregrate in the non-surgical repair of perforating invasive cervical resorption. Med Oral Patol Oral Cir Bucal. 2008; 13(10):E678-E680. 23. Yilmaz HG, Kalender A, Cengiz E. Use of mineral trioxide aggregate in the treatment of invasive cervical resorption: a case report. J Endod. 2010;36(1):160-163. 24. Zarrabi MH, Javidi M, Jafarian AH, Joushan B. Histologic assessment of human pulp response to capping with mineral trioxide aggregate and a novel endodontic cement. J Endod. 2010;36(11):1778-1781. 25. Asgary S, Nosrat A. Concurrent intentional replantation of maxillary molars using a novel root-end filling biomaterial: a case report. Gen Dent. 2013;62(3):3033. 26. Asgary S, Ahmadyar M. Vital pulp therapy using calcium-enriched mixture: an evidence-based review. J Conserv Dent. 2013;16(2):92-98. 27.Parirokh M, Torabinejad M. Mineral trioxide aggregate: a comprehensive literature review—Part III: clinical applications, drawbacks, and mechanism of action. J Endod. 2010;36(3):400-413. 28. Marao HF, Panzarini SR, Aranega AM, et al. Periapical tissue reactions to calcium hydroxide and MTA after external root resorption as a sequela of delayed tooth replantation. Dent Traumatol. 2012;28(4):306-313. Manufacturers BioniqueDent, Tehran, Iran www.bioniquedent.com (website suspended) Coltene/Whaledent, Inc., Cuyahoga Falls, OH 330.916.8800, www.coltene.com Office Design Evaluation of 3 dental unit waterline contamination testing methods Nuala Porteous, BDS, MPH n Yuyu Sun, PhD n John Schoolfield, MS Previous studies have found inconsistent results from testing methods used to measure heterotrophic plate count (HPC) bacteria in dental unit waterline (DUWL) samples. This study used 63 samples to compare the results obtained from an in-office chairside method and 2 currently used commercial laboratory HPC methods (Standard Methods 9215C and 9215E). The results suggest that the Standard Method 9215E is not suitable for application to DUWL quality monitoring, due to the T he water that is supplied via dental unit waterline (DUWL) tubing to air/water syringes, handpieces, and ultrasonic scalers in a typical dental unit is fed directly from the main water supply or via a self-contained reservoir on the dental unit itself. DUWL tubing typically is 2 mm in diameter and made of either polyvinyl chloride or polyurethane. This tubing forms a complex network inside a dental unit, resulting in a high ratio of tubing surface area to water volume.1 These factors, along with the periodic pooling of stagnant water inside the tubing, facilitate an ideal environment for bacterial growth and biofilm formation (up to 50µ thick) comprised of a heterogeneous population of organisms.2,3 Microorganisms from the biofilm are continuously shed as the water flows through the DUWL tubing, resulting in microbial contamination of the patient treatment water.4 The Centers for Disease Control and Prevention (CDC) recommends that the water used in dental offices should meet the drinking water standard established by the US Environmental Protection Agency (EPA) of <500 colony forming units per milliliter (CFU/ml) for routine dental treatment output water.5,6 In order for dental practitioners to comply with these guidelines, DUWL monitoring should be performed as recommended by the dental unit manufacturers.5 Waterline monitoring can be done in-office with chairside kits or via commercial laboratories. The purpose of monitoring is to measure the heterotrophic (organisms that use a carbon source for survival) plate count (HPC) of DUWL samples. detection of limited numbers of heterotrophic organisms at the required 35°C incubation temperature. The results also confirm that while the in-office chairside method is useful for DUWL quality monitoring, the Standard Method 9215C provided the most accurate results. Received: May 27, 2014 Accepted: September 17, 2014 Currently, there is only 1 in-office, chairside kit available: the HPC Sampler (EMD Millipore), consisting of a removable dip paddle contained in a plastic sampler. The dip paddle contains a 0.45µ filter and an absorbent pad with dehydrated agar medium which absorbs 1 ml of the liquid sample, facilitating the recovery of stressed (that is, partially sanitized or nutritionally starved) aerobic bacteria in 7 days. According to the manufacturer, this method can produce accurate readings up to 300 CFU/ml; all counts >300 CFU/ ml are considered too numerous to count (TNTC).7 There is evidence from previous studies to show that, although the HPC Sampler underestimates bacterial counts compared with other methods, it is useful as a screening tool for regular DUWL quality monitoring in dental offices to ensure the water used in the treatment of patients meets the CDC/EPA recommendation of <500 CFU/ml.8-10 Dental offices can also utilize services offered by commercial laboratories for a more accurate assessment of water quality. Waterline samples are collected and mailed using kits that are supplied to offices by the commercial entities. Standard laboratory methods, as published in the “Standard Methods for the Examination of Water and Wastewater”(hereafter referred to as Standard Methods), are recommended by the American Public Health Association, American Water Works Association, and Water Environment Federation.11 The list includes 4 standard methods and 5 types of media for use in different combinations as appropriate for testing purposes.11 www.agd.org Standard Method 9215C (a spread plate method on R2A medium) has long been considered the gold standard for analysis of DUWL quality.12 This procedure, using a low nutrient R2A formulation (Becton, Dickson & Company) and room temperature incubation for 7 days, was designed for the detection of common water organisms. The disadvantages of this method are that it is time-consuming to prepare the R2A and it relies on a small volume of liquid (0.1 ml), which can become quickly absorbed if the agar dries out.11 Standard Method 9215E (SimPlate for HPC, IDEXX Laboratories, Inc.) is a user-friendly method that has been included in the list of Standard Methods in recent years.11 A proprietary enzyme substrate is mixed with the water sample, and as bacteria metabolize the substrate they fluoresce after 48 hours of incubation at 35°C. The number of fluorescent wells are counted and converted to the most probable number (MPN), using a table provided by the manufacturers. The maximum MPN/ml recorded from an undiluted sample is 73.8; for more highly contaminated water samples, 10-fold serial dilutions can be used.13 Since its introduction as a Standard Method, SimPlate for HPC has become widely used in commercial laboratories, and dental offices that use a mail-in laboratory service may be obtaining their results from this method. A previous study by the authors found that bacterial counts were underestimated on the SimPlate for HPC compared to R2A agar.14 The purpose of this experiment was to expand on those findings and to compare bacterial counts and genera General Dentistry January/February 2015 41 Office Design Evaluation of 3 dental unit waterline contamination testing methods from all 3 currently available monitoring methods: the spread plate R2A (Method 9215C), the SimPlate for HPC (Method 9215E), and the in-office HPC Sampler. discarded and the Sampler was incubated at room temperature for 7 days, at which point CFU/ml were recorded using the comparison chart provided by the manufacturer.7 Materials and methods Molecular identification A selection of HPC Samplers and R2A plates with the largest bacterial colonies was transported to the Department of Microbiology at the University of Texas Health Science Center at San Antonio (UTHSCSA) for molecular identification, and a sequence-based approach using the 16s ribosomal DNA regions as targets for the molecular identification isolates was performed.17 The experiment was designed to collect an approximately uniform distribution of water sample contamination based on 3 source types and 7 exposure durations yielding a total of 63 waterline samples. Sterile collection bottles (100 ml), each containing sodium thiosulfate to neutralize residual chlorine (IDEXX Laboratories, Inc.) were used to collect samples from the handpiece lines, the air/water syringe lines, and the source tap water in 21 randomly selected dental operatories in a teaching institution. Each sample was cultured on HPC Sampler, R2A agar (Method 9215C), and SimPlate for HPC (Method 9215E) according to manufacturer-recommended methods. The pH of the source tap water and the residual free chlorine level (mg/l) were tested before the experiment and were found to be 7.2 and 0.5mg/l, respectively. These levels were assumed to remain constant as previous readings in the institution had shown this to be the norm.15 Sample cultures All laboratory procedures were conducted by 1 laboratory technician. A 10-fold serial dilution of each sample was made with phosphate buffer solution. For Method 9215C, 0.1 ml of each sample was spread on R2A plates in triplicate, incubated at room temperature, and the microbial CFU/ml was recorded after 7 days.11 For Method 9215E, 10 ml of each solution were placed in the center of the SimPlates and the manufacturer’s instructions were followed. Plates were incubated for 48 hrs at 35°C, and the MPN/ml was calculated.16 Following the calculation of MPN/ml, liquid was collected (using an inoculating loop) from randomly selected fluorescent wells, then spread on R2A plates and incubated at room temperature for 7 days to prepare isolates for molecular identification. For HPC Sampler cultures, an undiluted 10 ml sample was placed in the outer sheath, and the dip paddle was replaced for 30 seconds until 1 ml was absorbed. The remainder of the DUWL sample was 42 January/February 2015 DNA isolation Isolates were suspended in 600 μl cell lysis buffer (blood Maxwell LEV kit, Promega Corporation) in a 0.5 ml microfuge tube. The suspension was bead-beaten for 45 seconds to 1 minute to aid in cell wall breakdown. The suspension was then pelleted for 3 minutes at maximum speed in a microfuge according to the manufacturer’s instructions. The supernatant was transferred to the Maxwell LEV cartridge and then mounted on the automated Maxwell system, resulting in 150 ng/μl of purified bacterial DNA after a 45-minute run. Polymerase chain reaction Polymerase chain reactions (PCR) were performed directly on 3 μl of the DNA supernatant in a 50 μl reaction using a 5 prime PCR Extender system (Thermo Fisher Scientific, Inc.), according to the manufacturer’s instructions. 16s amplicons were obtained using primers 27F and 1525R. Amplifications were performed in a PTC-100 thermocycler (MJ Research, Inc.) using the preprogrammed, 3-step protocol as the standard program for all reactions, consisting of 35 cycles using an annealing temperature of 55°C and 1 minute extension time. A 5 μl aliquot of the PCR reaction was run on a 0.7% agarose gel and stained with ethidium bromide to confirm amplification. The remaining PCR reaction (45 μl) was run on a gel as described above, then purified using the Wizard SV Gel and PCR Clean-Up System (Promega Corporation), eluted in 30 μl sterile water according to the manufacturer’s instructions, and incubated with proteinase K at 56°C for 15 minutes. General Dentistry www.agd.org Sequencing DNA obtained from the PCR reaction was prepared for sequencing by cleaning with a Qiaprep Spin Miniprep Kit (Qiagen Sciences, Inc.) according to manufacturer’s instructions. The purified DNA was sequenced at the UTHSCSA Advanced Nucleic Acids Core facility. Sequences were then used to perform individual nucleotidenucleotide searches of the ribosomal 16s region using the BLASTn algorithm at the National Center for Biotechnology Information website.18 Identifications were calculated based on a percentage made from the alignment matches obtained from the top 3 BLAST searches for the 16s region to yield a variety level identification. The 3 highest percent identities for each isolate were analyzed for bacterial identification. Statistical analysis For the 3 types of detection methods, all possible pairwise Pearson and/or Spearman correlation coefficients with corresponding 95% confidence intervals were performed to determine if any significant association was observed among the 3 measurement methods, with log transformations performed if appropriate. Correlations were performed for all waterline samples and, if appropriate, separately for each waterline sample source type. Statistical analyses and graphics were performed using Stata 13.0 (StataCorp LP). Results As expected, the R2A measures approximated an exponential distribution; however, the SimPlate for HPC values approximated a uniform distribution ranging from a minimum of 0.4 MPN/ml to the maximum 73.8 MPN/ml, followed by 12 (19%) samples with unspecified values >73.8 MPN/ml, as the corresponding 110 dilution plates did not provide any results. There were also 4 samples based on a 110 dilution that had values ranging from 112 to 440 MPN/ml and 1 handpiece sample that could not be assayed due to technical error. For the purposes of graphs and correlations, an arbitrary value of 80 MPN/ml was used to represent all SimPlate for HPC values >73.8 MPN/ml. Table 1. HPC from DUWL samples Dental unit Sample source 1 Handpiece Air/water Source water 2 4 59 1000 Handpiece 293 2.1 12 142,000 41.4 1000 Air/water 6,570 26.6 1000 Source water 8,430 29.9 1000 Handpiece 138,000 31.1 1000 Air/water 392,000 47.0 1000 Handpiece 86.7 341,000 0.4 33 55.5 1000 235,000 44.0 1000 1,470 1.9 360 Dental unit Sample source 12 133 15.1 39 Handpiece 411,000 55.5 1000 Air/water 244,000 80.0 b 1000 387 0.2 86 Handpiece 795,000 257.0 1000 Air/water 722,000 37.2 1000 213 1.0 151 Handpiece 233,000 73.8 1000 Air/water 362,000 62.3 1000 417 2.6 73 Handpiece Air/water Source water 17 80.0 b 1000 73.8 600 1000 Air/water Source water 62.3 0 573,000 73.8 1000 327 73.8 1000 Handpiece 361,000 239.0 1000 Air/water 535,000 62.3 1000 Handpiece Air/water Source water 73.3 178,000 1.0 80.0 10 0.6 Handpiece 151,000 80.0 Air/water 323,000 55.5 Source water Handpiece Air/water Source water 1000 b 1000 NA 1000 70,700 112.0 1000 37.2 216 Handpiece 42,300 283 80.0 b 1000 Air/water 13,100 80.0 b 1000 527 73.8 116 Handpiece 343,000 440.0 1000 Air/water 226,000 80.0 b 1000 367 13.2 36 Handpiece 91,300 55.5 1000 1000 Air/water 57,700 80.0 b 1000 Source water 51,300 73.8 1000 1000 21 24,600 33.9 1000 243,000 41.4 1000 a b 176,000 39.2 1000 27,700 47.0 1000 Results for each of the methods can be seen in Table 1. The HPC Sampler detection method showed that 46 (73%) of the dip paddle surfaces were entirely covered with TNTC small microbial colonies. For 2 handpiece samples, no HPC 33,400 Source water 1 b Handpiece Source water 20 2,390 Air/water Source water 19 20 47.0 39,900 18 39 101,000 1000 50.7 642,000 47.0 1000 68.0 Handpiece 1000 1000 80.0 b 252,000 1000 76.7 62.3 80.0 b 115,000 284,000 27.6 8,370 139,000 Handpiece Handpiece 1,850 0 1000 80.0 80.0 b Source water 16 CFU/ml b 47,300 Source water 15 HPC sampler MPN/ml 543,000 Source water 14 SimPlate CFU/ml Handpiece Source water 13 R2A agar Air/water Air/water Source water 11 1000 23.1 1000 Source water 10 23.9 1,130 37.2 Air/water 9 87,000 23.1 Source water 8 1000 a 102,000 Source water 7 26.6 CFU/ml 494,000 Air/water 6 61,300 MPN/ml HPC sampler Handpiece Source water 5 CFU/ml SimPlate Air/water Source water 3 R2A agar 1000 CFU/ml MPN >73.8/ml Abbreviations: CFU, colony forming units; DUWL, dental unit waterline; HPCs, heterotrophic plate counts; MPN, most probable number; NA, not available. counts were detected; otherwise, all handpiece and air/water samples counts were TNTC. For the purposes of graphs and correlations, an arbitrary value of 1,000 CFU/ml was used to represent TNTC results, and the 2 handpiece www.agd.org samples for which the HPC Sampler failed to detect CFUs were excluded as having implausible results. Specific HPC counts were detected for 14 of 21 source water samples. Due to the characteristics of the distribution of HPC measures, General Dentistry January/February 2015 43 Office Design Evaluation of 3 dental unit waterline contamination testing methods Recovered microorganisms As seen in Table 3, 16 genera of bacteria were recovered. The most commonly occurring genus was Sphingomonas, and only 2 species—Cupriavidus metallidurans and Sphingomonas parapaucimobilis—were found on all 3 culture media. Micrococcus luteus was the only gram-positive species found. All other recovered bacteria were gram-negative. Discussion This article describes an evaluation of 3 currently available methods for monitoring HPC bacteria in DUWLs. The SimPlate for HPC (Method 9215E) recovered the lowest numbers of microorganisms and the highest readings were found on spread plate R2A (Method 9215C), although it must be noted that all HPC methods enumerate only a fraction of microorganisms in any water 44 January/February 2015 Table 2. Correlation coefficients (95% confidence interval). Pearson Sample source Spearman R2A with SimPlate for HPC All 0.607 (0.421, 0.744) 0.475(0.256, 0.648) Handpiece 0.103 (-0.356, 0.522) 0.174 (-0.291, 0.572) Air/water -0.068 (-0.486, 0.375) -0.268 (-0.627, 0.185) Source water 0.481 (0.062, 0.756) 0.521 (0.115, 0.778) All 0.650 (0.474, 0.776) Source water 0.573 (0.188, 0.805) Millipore with SimPlate for HPC 0.598 (0.406, 0.740) 0.624 (0.263, 0.832) R2A with Millipore All 0.871 (0.793, 0.921) 0.734 (0.592, 0.832) Source water 0.795 (0.554, 0.913) 0.797 (0.557, 0.914) Chart. R2A with SimPlate for HPC method scatterplot, displaying legend markers indicating the range of the corresponding HPC Sampler value for each sample. 1,000,000 100,000 10,000 R2A (CFU/ml) correlations were performed for all samples and for source water samples only (Table 2). For the R2A with SimPlate for HPC, the overall Pearson correlation coefficient of 0.607 was moderate, while the corresponding Spearman rank correlation coefficient of 0.475 was lower. Correlations for each source type showed similar results for source water samples and poorer results for handpiece and air/ water samples. To depict the pairwise association, a scatterplot was generated displaying the paired results for each sample with symbols indicating the source type (Chart). For the HPC Sampler with SimPlate for HPC, the overall Pearson correlation coefficient of 0.650 was significantly lower than the overall Pearson correlation coefficient of 0.871 for SimPlate for HPC with R2A. Similarly, the corresponding Spearman correlation for HPC Sampler with R2A was higher than that for SimPlate with R2A, but the 2 Spearman correlations were not significantly different. When restricted to the source water samples, the HPC Sampler with SimPlate for HPC Pearson correlation coefficient of 0.573 was significantly lower than the HPC sampler with R2A coefficient of 0.795, while the corresponding Spearman correlations were not significantly different. 1000 100 10 HPC sampler (CFU/ml) >500 100-500 50-99 1-49 0 010 20304050 607080 SimPlate for HPC (MPN/ml) Note that 2 handpiece samples for which no CFUs were detected by HPC Sampler were excluded. All samples with R2A >1500 CFU/ml had HPC Sampler values >500 CFU/ml, while only 1 sample with R2A <1500 CFU/ml had an HPC Sampler value >500 CFU/ml. sample and no single method will recover all genera.19 The overall results are not altogether unexpected, since the media composition and incubation parameters were specifically designed to recover different microbial populations. General Dentistry www.agd.org Statistical analysis showed moderate correlations between Method 9215E and the other 2 methods, while Method 9215C and HPC Samplers had high correlations. Correlations based on source tap water samples involved fewer arbitrary Table 3. Bacteria recovered from DUWL samples. Acidovorax sp.a Methylobacterium radiotolerans Sphingomonas sanguinis Acidovoraxcitrulli Methylobacterium rhodesianum Sphingomonas trueperi Acidovoraxtemperans Methylobacterium thiocyanatum Sphingomonas yunnanensis Afipia sp. Micrococcus luteus Sphingopyxis alaskensis Blastomonas natatoria Novosphingobium stygium Sphingopyxis chilensis Bradyrhizobium sp. Pseudomonas koreen c Xenophilus aerolatus Bradyrhizobium yuanmingens Pseudomonas libane c Xulophilus ampelinus Caulobacter segnis Ralstonia sp. a Grown on R2A and Millipore HPC Samplers Cupriavidus basilensis Sphingobium sp. Cupriavidus metallidurans b Sphingobium amiense b Methylobacterium extorquens Sphingomonas sp. c Methylobacterium oryzae Sphingomonas adhaesiva Methylobacterium populi Sphingomonas parapaucimobilis b approximation values, resulting in a decrease in Pearson correlations and an increase in Spearman correlations. Unlike the other 2 laboratory methods, serial dilutions of samples were not done prior to culturing on HPC Samplers due to its purposeful design as an in-office, chairside monitoring device. As stated earlier, previous studies have shown that HPC Samplers underestimate bacterial counts when compared to the spread plate R2A agar method, and some have attributed this to its failure to grow certain phenotypes.20,21 The results of this study concur with those findings. However, this study also confirms the high sensitivity of the HPC Samplers, as microbial counts on the majority of the paddles were TNTC and 5 different species of bacteria were detected. For the 2 handpiece samples in which zero bacterial growth was recovered on HPC Samplers, a plausible explanation may be variation among kits, as it was unlikely due to laboratory error (based on the reliability of the standard laboratory methods employed). The spread plate R2A agar (Method 9215C) has long been considered the gold standard for application to DUWL monitoring with the advantage of producing a true assessment of HPC contamination levels. In this study, accurate counts were obtained using serial dilutions, and 14 different genera of bacteria were detected on R2A plates. Grown on all 3 media Grown on Millipore HPC Samplers only No symbol: grown on R2A agar only The inclusion of SimPlate for HPC (Method 9215E) in the list of the Standard Methods endorses its use for analysis of drinking water and source water sampes.11 It is recommended as an alternative to the pour plate method (9215A), which uses high nutrient plate count agar to test for general EPA compliance monitoring; studies have demonstrated good correlation between the 2 methods.11,13,16 Both 9215A and 9215E methods require incubation periods of 48 hours at mammalian physiological incubation temperature (35°C), favoring the growth of bacteria from human and animal wastes.22 However, a previous study showed that Method 9215E showed lower microbial counts when compared to the membrane filter method (9215D), which utilizes low nutrient R2A agar and incubation periods of 48 hours at 22°C-28°C.13 Lower incubation temperature (22°C-28°C), along with a longer incubation time favor the growth of indigenous aquatic bacteria.22 SimPlate for HPC was a method designed for higher incubation temperatures, and the results of this study add to the body of existing scientific evidence showing that Method 9215E underestimates microbial contamination at 22°C-28°C.13,14,16 Significance of microorganisms recovered Culture plates that were selected for organism identification were based on recovered colony size, so the number of www.agd.org recovered organisms represents a mere snapshot of the total bacterial population. Not surprisingly, due to the limited number of microorganisms isolated on SimPlate for HPC, only 2 bacterial species were identified. However, it must also be noted that this method is not designed for recovering particular organisms, as stated in the Standard Methods.11 One gram-positive organism was identified on R2A: M. luteus, which is ubiquitously found in soil, dust, air, and water. Cases of infective endocarditis due to M. luteus have been reported in the literature.23 All other microorganisms were gramnegative, which are known to have lipopolysaccharide molecules (endotoxins) in their cell wall that can trigger inflammatory responses in humans. Several studies have reported a significant association between the presence and severity of asthma and a raised concentration of airborne gramnegative bacteria in the indoor environment.24 A significant correlation between endotoxin levels and high bacterial load in DUWLs has also been reported.25 Two species of Pseudomonas isolated on the HPC Samplers in this study have previously been recovered from DUWLs and reported as the causative organisms of postoperative dental infections and respiratory infections in immunocompromised patients.26,27 Only 2 bacterial types were common to the 3 culture methods tested in the study: Cupriavidus metallidurans and Sphingomonas parapaucimobilis; these were the only bacterial species recovered on SimPlate for HPC, verifying the limitations of this culture method for detection of common water organisms. C. metallidurans belongs to the α-Proteobacteria group, known to be the predominant survivor in chlorinated water distribution systems.28,29 The most frequently isolated genera in this study were Sphingomonas, also closely aligned with the phylogenic group α-Proteobacteria, and previously found in DUWL samples and ultrapure water.2,15,29,30 A review of nosocomial infections concluded that the species S. parapaucimobilis has emerged in recent years as an opportunistic pathogen as it has been associated with many cases of bacteremia and other systemic infections in immunocompromised patients.31 General Dentistry January/February 2015 45 Office Design Evaluation of 3 dental unit waterline contamination testing methods Conclusion The variety of potentially pathogenic organisms recovered from waterlines in this study reinforces the need for monitoring DUWL quality to ensure the delivery of high quality dental patient treatment water. The study confirmed that Millipore HPC Samplers are useful for routine in-office, chairside DUWL quality monitoring when the benchmark CDC recommended level of <500 CFU/ml is used. The study also confirmed that the spread plate R2A agar method (9215C) provides the most accurate analysis of DUWL quality. The laboratory SimPlate for HPC method (9215E) failed to detect microbial contamination of DUWL samples to the same extent as Method 9215C, most likely due to the specific design of SimPlate for HPC for the recovery of fast-growing organisms at 35°C. While Method 9215E clearly has value for application in EPA compliance monitoring, this study found that it is not acceptable for application in DUWL quality monitoring, when quantification of slowgrowing water organisms at 22°C-28°C and a correct assessment of dental patient treatment water quality are required. Dental offices can reliably use in-office, chairside Millipore HPC Samplers to screen DUWL quality, ensuring that patient treatment water is compliant with the EPA/CDC recommendation of <500 CFU/ml. However, for offices that rely on commercial laboratories to provide an accurate assessment of their DUWL quality, it is recommended that the spread plate R2A method (9215C) be requested, rather than the SimPlate for HPC method (9215E), when DUWL samples are submitted for analysis. Author information Dr. Porteous is an associate professor, Department of Comprehensive Dentistry, University of Texas Health and Science Center at San Antonio (UTHSCSA), where Mr. Schoolfield is a consultant biostatistician, Department of Periodontics. Dr. Sun is an associate professor, Department of Chemistry, University of Massachusetts in Lowell. Acknowledgments Research reported in this article was supported by the National Institute of Dental 46 January/February 2015 & Craniofacial Research of the National Institutes of Health (NIH) under Award Number R01 DE018707-05. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH. Drs. Porteous and Sun are co-principal investigators and Mr. Schoolfield is a co-investigator. The authors wish to thank Monica Herrera, MD, research associate, Department of Microbiology, UTHSCSA, for her work on molecular analysis of organisms at the time of this study. Disclaimer The authors have no financial, economic, commercial, and/or professional interests related to topics presented in this article. References 1. Mills SE. The dental unit waterline controversy: defusing the myths, defining the solutions. J Am Dent Assoc. 2000;131(10):1427-1441. 2. Szymanska J. Bacterial contamination of water in dental unit reservoirs. Ann Agric Environ Med. 2007;14(1): 137-140. 3. Cunningham AB, Lennox JE, Ross RJ, eds. Biofilm growth and development. In: Biofilms: The Hypertextbook. Available at: http://www.biofilmbook.com. Accessed November 7, 2014. 4. Lenz AP, Williamson KS, Pitts B, Stewart PS, Franklin MJ. Localized gene expression in Pseudomonas aeruginosa biofilms. Appl Environ Microbiol. 2008;74(14): 4463-4471. 5. Kohn WG, Collins AS, Cleveland JL, et al. Guidelines for infection control in dental health-care settings – 2003. MMWR Recomm Rep. 2003;52(RR17):1-61. 6. United States Environmental Protection Agency. National Primary Drinking Water Regulations. Available at: http://www.epa.gov/safewater/contaminants/ index.html. Accessed November 7, 2014. 7. EMD Millipore [product guide]. Available at: http:// www.millipore.com/catalogue/module/C10712. Accessed November 7, 2014. 8. Momeni SS, Tomline N, Ruby JD, Dasanayake AP. Evaluation of in-office dental unit waterline testing. Gen Dent. 2012;60(3):142-147. 9. Morris BF, Vandewalle KS, Hensley DM, Bartoloni JA. Comparison of in-office dental unit waterline test kits. Mil Med. 2010;175(11):901-906. 10. Bartoloni JA, Porteous NB, Zarzabal LA. Measuring the validity of two in-office water test kits. J Am Dent Assoc. 2006;137(3):363–371. 11. American Water Works Association, American Public Health Association, Water Environment Federation. Microbiological examination. In: Rice EW, Baird RB, Eaton AD, Clesceri LS, eds. Standard Methods for the Examination of Water and Wastewater. 22nd ed. Washington, DC; 2012: 9.49-9.52. 12. De Paola LG, Mangan D, Mills SE, et al. A review of the science regarding dental unit waterlines. J Am Dent Assoc. 2002;133(9):1199-206; quiz 1260. 13. Stillings A, Herzig D, Roll B. Comparative Assessment of the Newly-Developed SimplateTM Method With the Existing EPA-Approved Pour Plate Method for the General Dentistry www.agd.org Detection of Heterotrophic Plate Count Bacteria in Ozone-Treated Drinking Water. International Ozone Association Conference, October 1998. Available at: https://www.idexx.com/resource-library/water/waterreg-article8B.pdf. Accessed November 10, 2014. 14. Porteous N, Sun Y, Dang S, Schoolfield J. A comparison of 2 laboratory methods to test dental unit waterline water quality. Diag Microbiol Infect Dis. 2013;77(3): 206-208. 15. Porteous N, Luo J, Hererra M, Schoolfield J, Sun Y. Growth and identification of bacteria in N-halamine dental unit waterline tubing using an ultrapure water source. Int J Microbiol. 2011;767314. 16. Jackson RW, Osborne K, Barnes G, et al. Multiregional evaluation of the SimPlate heterotrophic plate count method compared to the standard plate count agar pour plate method in water. Appl Environ Microbiol. 2000;66(1):453-454. 17. Frank JA, Reich CI, Sharma S, Weisbaum JS, Wilson BA, Olsen GJ. Critical evaluation of two primers commonly used for amplification of bacterial 16S rRNA genes. Appl Environ Microbiol. 2008;74(8):2461-2470. 18. National Center for Biotechnology Information. Blast: Basic Local Alignment Search Tool. Available at: http:// blast.ncbi.nlm.nih.gov/Blast.cgi. Accessed November 10, 2014. 19. Allen MJ, Edberg SC, Reasoner DJ. Heterotrophic plate count bacteria—what is their significance in drinking water? Int J Food Microbiol. 2004;92(3):265-274. 20. Smith RS, Pineiro SA, Singh R, Romberg E, Labib ME, Williams HN. Discrepancies in bacterial recovery from dental unit water samples on R2A medium and a commercial sampling device. Current Microbiol. 2004; 48(4):243-246. 21. Cohen ME, Harte JA, Stone ME, O’Connor KH, Coen ML, Cullum ME. Statistical modeling of dental unit water bacterial test kit performance. J Clin Dent. 2007; 18(2):39-44. 22. Reasoner DJ. Heterotrophic plate count methodology in the United States. Int J Food Microbiol. 2004;92(3): 307-315. 23. Miltiadous G, Elisaf M. Native valve endocarditis due to Micrococcus luteus: a case report and review of the literature. J Med Case Rep. 2011;5:251. 24. Rennie DC, Lawson JA, Kirychuk SP, et al. Assessment of endotoxin levels in the home and current asthma and wheeze in school-age children. Indoor Air. 2008; 18(6):447-453. 25. Huntington MK, Williams JF, Mackenzie CD. Endotoxin contamination in the dental surgery. J Med Microbiol. 2007;56(Pt 9):1230-1234. 26. Martin MV. The significance of the bacterial contamination of dental unit water systems. Br Dent J. 1987; 163(5):152-154. 27. Langton Hewer SC, Smyth AR. Antibiotic strategies for eradicating Pseudomonas aeruginosa in people with cystic fibrosis. Cochrane Database Syst Rev. 2009;(4): CD004197. 28. von Rozycki T, Nies DH. Cupriavidus metallidurans: evolution of a metal-resistant bacterium. Antonie van Leeuwenhoek. 2009;96(2):115-139. 29. Williams MM, Domingo JW, Meckes MC, Kelty A, Rochon HS. Phylogenic diversity of drinking water bacteria in a distribution system simulator. J Appl Microbiol. 2001;96(5):954-964. 30. Oie S, Oomaki M, Yorioka K, et al. Microbial contamination of ‘sterile water’ used in Japanese hospitals. J Hosp Infect. 1998;38(1):61-65. 31. Ryan MP, Adley CC. Sphingomonas paucimobilis: a persistent Gram-negative nosocomial infectious organism. J Hosp Infect. 2010;75(3):153-157. Manufacturers Becton, Dickson & Company, Franklin Lakes, NJ 888.237.2862, www.bd.com EMD Millipore, Billerica MA 781.533.6000, www.emdmillipore.com IDEXX Laboratories, Inc., Westbrook, ME 800.548.6733, www.idexx.com MJ Research, Inc., St. Bruno, Quebec, Canada 450.461.6245, mj-research.com Promega Corporation, Madison, WI 608.274.4330, www.promega.com Qiagen Sciences, Inc., Germantown, MD 240.686.7700, www.qiagen.com StataCorp LP, College Station, TX 800.782.8272, www.stata.com Thermo Fisher Scientific, Inc., Waltham, MA 800.678.5599, www.thermofisher.com www.agd.org General Dentistry January/February 2015 47 Anesthesia and Pain Control Local anesthetic calculations: avoiding trouble with pediatric patients Mana Saraghi, DMD n Paul A. Moore, DMD, PhD, MPH n Elliot V. Hersh, DMD, MS, PhD Local anesthetic systemic toxicity (LAST) is a rare but avoidable consequence of local anesthetic overdose. This article will review the mechanism of action of local anesthetic toxicity and the signs and symptoms of LAST. Due to physiologic and anatomic differences between children and adults, LAST occurs more frequently in children; particularly when 3% mepivacaine is administered. The calculation of the maximum recommended dose based on mg/lb body weight, Clark’s rule, and the Rule of 25 in order to prevent LAST A pproximately 1 million cartridges of local anesthetic are used each day in the United States.1 Local anesthetic systemic toxicity (LAST) is dose-related and although rare, occurs more frequently in small children than adults. LAST occurs more frequently when the patient is administered concomitant central nervous system (CNS) depressants, such as opioid/sedative medications.2-9 The following case serves as a reminder to proceed cautiously when administering routine local anesthetic, always keeping weight-based dosing in mind. A 50-lb, 8-year-old girl with a history of extensive caries and dental fear—but otherwise no medical problems, diseases, or allergies—presented for multiple extractions. For the initial sedation, the patient received oral promethazine, as well as nitrous oxide-oxygen inhalational sedation. A half hour later, the sedation was supplemented with an intramuscular dose of meperidine. After another half hour had elapsed, the child received injections of 6 cartridges of 3% mepivacaine plain (without a vasoconstrictor). Seizures and respiratory distress followed 5 minutes later. Resuscitation efforts followed, but were unsuccessful, and the patient died of anoxic encephalopathy.5 The most common cause of morbidity and mortality due to LAST is respiratory depression or apnea.10 LAST occurs more frequently in children when 3% mepivacaine is administered, with the false presumption that a local anesthetic without a vasoconstrictor will have a 48 January/February 2015 will also be reviewed, as well as the appropriate treatment procedures for a local anesthetic overdose. Received: July 17, 2013 Revised: October 30, 2013 Accepted: February 10, 2014 Key words: local anesthetic toxicity, systemic toxicity, maximum recommended dose, Clark’s rule, lidocaine, mepivacaine shorter duration of soft tissue anesthesia and prevent postoperative self-inflicted lip and cheek trauma.10,11 Local anesthesia: mechanism of action and toxicity Local anesthetics are essential for intraoperative dental analgesia; they work by blocking sodium channels in neurons so that pain signals from the periphery cannot be transmitted to the CNS. LAST is mediated by the same mechanism when the maximum recommended dose (MRD) is exceeded. This dose-related toxicity is especially important as the sodium channels in the cardiovascular system are blocked along with those in the CNS.12,13 Regardless of which local anesthetic is administered, the same progression of effects on the CNS and cardiovascular system occur with increasing plasma levels of local anesthetic.12,13 Symptoms of early toxicity consist of numbness and tingling of the mouth and lips, metallic taste, diplopia, tinnitus, nausea, dizziness, and drowsiness.12,13 These reactions are usually self-limiting and often are due to a mild overdose or an inadvertent intravascular injection. As the plasma concentrations of local anesthetic increase, the inhibitory neurons in the CNS are blocked, leaving excitatory neurons unopposed. Clinically, this manifests as tremors and tonic-clonic (also known as grand mal) seizures. CNS arousal may stimulate the cardiovascular system, possibly resulting in hypertension, tachycardia, and increased cardiac output.12,13 At higher plasma levels of local anesthetic, both excitatory and inhibitory General Dentistry www.agd.org neurons are blocked to such a profound level that CNS and respiratory depression, unconsciousness, and respiratory arrest can occur. At even higher plasma concentrations, systemic vasodilation results in significant hypotension and cardiovascular depression. Local anesthetics also block sodium channels in the myocardium, resulting in bradycardia. Bradycardia is a major cause of concern when bupivacaine is used, as it can induce a use-dependent blockade at normal heart rates.12,13 Because of its extended duration of action, bupivacaine is rarely indicated for children. The sequelae of depressed cardiac conduction include atrioventricular block, ventricular arrhythmias, cardiac arrest, and ultimately, death. A local anesthetic overdose can result in significant morbidity and mortality unless life support interventions can be initiated following standard basic and advanced cardiac life support guidelines.12,13 Concomitant opioid sedative administration will augment respiratory depression and decrease the seizure threshold of local anesthetics.3,5,6,12-15 LAST: a greater tendency in pediatric patients There are some important physiological differences between children and adults that play a role in the greater tendency for LAST to be reported in the pediatric population. Seated in the dental chair, a child may appear deceptively large. The reason that the child appears to be larger is that in the dental chair—with a bib, napkin, or blanket—only the child’s disproportionately large head is visible.4 This 6’ 6’ 3’ 1.00 Head size 0.75 5’ 3’ Height 4’ 2’ 1’ Figure. Diagram comparing the relative proportions in height vs head size between a 3.5-year-old child and an adult. Table 1. Local anesthetic calculation: amount of local anesthetic in cartridges. 2% anesthetic = 2 grams/100 ml in volume = 2000 mg/100 ml = 20 mg/ml 3% anesthetic = 3 grams/100 ml in volume = 3000 mg/100 ml = 30 mg/ml 1 cartridge of local anesthetic is 1.8 ml in volume (exception: 4% articaine has 1.7 ml) Therefore… 2% cartridge: 20 mg/ml x 1.8 ml/cartridge = 36 mg/cartridge 3% cartridge: 30 mg/ml x 1.8 ml/cartridge = 54 mg/cartridge makes it more critical to determine the maximum dose and number of cartridges based on the child’s actual weight. The following example of a 3.5-year-old child illustrates the point that children often appear deceptively large and how this may prompt the dentist to overestimate the child’s size based solely on appearances.4 Because the head develops quickly during early childhood, children have disproportionately large heads; at the age of 3.5, a child’s head is nearly 75% of the size of his/her adult counterpart.4,5 However, the same child has only 50% of the height, 25% of the blood volume, and 20% of the weight compared to his/her adult counterpart (Figure).4 The child’s airway is also different, with narrower nasal passages, larynx, and trachea. Meanwhile, children have relatively larger tongues, tonsils, and adenoids than adults. These anatomic differences—coupled with the heightened susceptibility to CNS and respiratory depressants—render children more vulnerable to losing airway patency.4 Local anesthetic selection: misconceptions about prolonged soft tissue numbness When treating children, it is important to inform parents or caregivers that close postoperative supervision is needed to prevent the child from biting their lips, cheeks, and tongue. While the soft tissues are still numb, significant trauma from lip and cheek biting can occur. There is a misconception that using a local anesthetic without a vasoconstrictor, such as mepivacaine 3% plain, will provide a shorter duration of soft tissue anesthesia www.agd.org than a local anesthetic with a vasoconstrictor, such as 2% lidocaine with 1:100,000 epinephrine.11,12 Mepivacaine does offer shorter pulpal anesthesia (20-40 minutes) as compared to lidocaine with epinephrine (60-90 minutes), but soft tissue anesthesia is similar between the 2 anesthetics: 120-180 minutes and 120-240 minutes for mepivacaine plain and lidocaine with epinephrine, respectively.11 Hersh et al found that “the onset of soft tissue numbness, peak numbness effects, and numbness duration were quite similar” when comparing 3% mepivacaine plain and 2% lidocaine with epinephrine.11 Using 3% mepivacaine plain instead of 2% lidocaine with epinephrine does not provide any benefit with respect to the prevention of postoperative lip/mouth trauma, but the higher concentration of local anesthetic in the 3% mepivacaine solution makes it easier to reach or exceed the MRD.3,4,11,16,17 A brief review of local anesthetic calculations illustrates this point: a 2% formulation of a drug means that there is 2 grams of drug in 100 ml volume. If 2 grams are in 100 ml, then 2000 mg are in 100 ml, which means that 20 mg are in each ml. Since a dental cartridge contains approximately 1.8 ml volume, then there are 36 mg drug per cartridge (Table 1). Similarly, when a drug is in a 3% formulation, there are 30 mg per ml, thus there are 54 mg per 1.8 ml dental cartridge. Therefore, a cartridge of 3% mepivacaine contains 50% more local anesthetic than a cartridge of 2% lidocaine; thus it would take less volume (or fewer cartridges) of the more concentrated drug (3% mepivacaine) to reach its respective MRD.11 Preventing local anesthetic toxicity: calculating appropriate weight-based dose Respecting weight-based dosing limits is essential, as previous cases of LAST have resulted in significant morbidity and mortality when dosing limits were exceeded.3,4,12,16,17 In a 1983 retrospective study, pediatric dental patients that received local anesthesia and opioid sedation—either local alone or local plus narcotic dose—exceeded their combined MRDs by a factor of ≥3; the result was either permanent brain damage or death.6 In a 1992 survey of local anesthetic use General Dentistry January/February 2015 49 Anesthesia and Pain Control Local anesthetic calculations: avoiding trouble with pediatric patients Table 3. Local anesthetic calculation for a 50 lb child based on Clark’s rule. 1. Calculate the MRD from each drug for a 50 lb child. Patient’s weight/150 lb adult x adult MRD = patient’s MRD Table 2. Local anesthetic calculations for a 50 lb child based on mg/lb. Adult MRD: 2% lidocaine with 1:100,000 epinephrine: 500 mg 1. Calculate the MRD for each drug for a 50 lb child. 3% mepivacaine plain: 400 mg 2% lidocaine with 1:100,000 epinephrine = 3.2 mg/lb x 50 lb = 160 mg Lidocaine with 1:100,000 epinephrine: 50/150 x 500 mg = 166 mg 3% mepivacaine plain = 2.6 mg/lb x 50 lb = 130 mg Mepivacaine plain: 50/150 x 400 mg = 133 mg 2. Determine the maximum number of cartridges based on the MRD. 2. Determine the maximum number of cartridges based on the MRD. 2% lidocaine with 1:100,000 epinephrine: 160 mg ÷ 36 mg/cartridge = 4.4a cartridges 2% lidocaine with 1:100,000 epinephrine: 166 mg ÷ 36 mg/cartridge = 4.62a cartridges 3% mepivacaine plain: 130 mg ÷ 54 mg/cartridge = 2.4b cartridges 3% mepivacaine plain: 133 mg ÷ 54 mg/cartridge = 2.46b cartridges In clinical terms, 4.5 cartridges. In clinical terms, 2.5 cartridges. Abbreviation: MRD, maximum recommended dose. In clinical terms, 4.5 cartridges. In clinical terms, 2.5 cartridges. Abbreviation: MRD, maximum recommended dose. a a b b among Florida dentists who routinely treated pediatric patients, a majority of the respondents used an absolute number of cartridges without accounting for the child’s age or weight.2 A clinician can prevent a local anesthetic overdose by calculating the MRD and the maximum number of cartridges by weight to appropriately administer local anesthetic in children; this dose per weight is contingent on calculations of a weight that is consistent with normal growth and development and normal lean body mass.18 Based on these calculations, the MRD of 2% lidocaine with 1:100,000 epinephrine is 3.2 mg/lb; for a patient ≥150 lbs, the adult MRD is 500 mg. The MRD of 3% mepivacaine plain is 2.6 mg/lb; for a patient >150 lbs, the adult MRD is 400 mg.18,19 Table 2 illustrates the calculation needed to derive the absolute maximum number of cartridges of 2% lidocaine with epinephrine and 3% mepivacaine plain that can be given to a child weighing 50 lb. This number is approximately 33% of the adult maximum number of cartridges. A vasoconstrictor (such as epinephrine) reduces the systemic absorption of a local anesthetic, and several pharmacokinetic studies have demonstrated that the average peak blood levels following maxillary infiltration injections were 3 times higher with 3% mepivacaine plain in comparison to 2% lidocaine with epinephrine.12,20,21 50 January/February 2015 Table 4. Local anesthetic calculation for a 50 lb child based on the Rule of 25. 1 cartridge/25 lb weight 1 cartridge/25 lb weight x 50 lb child = 2 cartridges of any local anesthetic or combination of local anesthetics for a 50 lb patient. Clark’s rule is another weight-based method for calculating the MRD.12 According to Clark’s rule, the dose of local anesthetic should be reduced by the ratio of the child’s weight to an adult weight of 150 lb.5 Thus, if a child weighs 50 lb, then he/she is 33% of the established adult weight. Therefore, the child’s MRD for any local would be 33% of the 150 lb adult MRD for a given local anesthetic. As stated before, the MRD for 2% lidocaine with epinephrine for a 150 lb adult is 500 mg, and the MRD for 3% mepivacaine plain is 400 mg. Therefore, the MRD for a 50 lb patient is 33% of the adult MRD, which calculates as 166 mg of 2% lidocaine with epinephrine (approximately 4.5 cartridges) or 133 mg of 3% mepivacaine plain (approximately 2.5 cartridges.) (Table 3).12 It is important to note that the effects of all local anesthetics, including toxicity, are mediated at the sodium channel in a dose-dependent fashion. The effects of various local anesthetics are additive. Once the MRD for 1 local anesthetic is General Dentistry www.agd.org administered, the patient cannot receive any other local anesthetics, including topical applications.22 Moore & Hersh describe a simplified alternative for calculating safe maximum doses using a conservative guideline.12 Described as the Rule of 25, this alternative calculation can be applied to all US dental local anesthetic formulations for healthy patients. The Rule of 25 states that 1 cartridge of any formulation marketed in the US may be used per 25 lb of weight. Therefore, 1 cartridge for a 25 lb patient, 2 cartridges for a 50 lb patient, 3 cartridges for a 75 lb patient, up to a maximum of 6 cartridges for patients ≥150 lbs (Table 4).12 The end result of the Rule of 25 is a lower number of cartridges administered to the child in comparison to other weight-based calculations (Table 5). Since the vast majority of local anesthetic morbidity and mortality reports involve children ≤8 years of age, the Rule of 25 may be more appropriate in this population than in calculations used for adults.12 Table 5. Summary of dosing calculations in a 50 lb child. MRD 2% lidocaine with 1:100,000 epinephrine Maximum cartridges with 2% lidocaine with 1:100,000 epinephrine MRD 3% mepivacaine plain Maximum cartridges with 3% mepivacaine plain Adult MRD Weight-based calculations Clark’s rule Rule of 25 500 mg 160 mg 166 mg N/A 13.5 4.5 4.5 2.0 400 mg 130 mg 133 mg N/A 7.5 2.5 2.5 2.0 Abbreviation: MRD, maximum recommended dose. When treating small children, it is advisable to determine the maximum number of local anesthetic cartridges needed for that appointment. Keep only this amount of cartridges on the tray, and do not discard any used cartridges until the appointment is over. This will precisely track the number of cartridges administered. Aspiration and slow injection will allow for recognition of inadvertent intravascular injection before the entire cartridge is injected into a vessel.22 Profound anesthesia can often be achieved in children with less than a full cartridge of anesthetic. Injecting slowly—approximately 30-60 seconds per cartridge—will minimize discomfort and allow retention of the local anesthetic at the target site rather than being flushed farther away.22 Rather than giving the entire predetermined amount of local anesthetic at the beginning of a procedure, it is preferable to reserve 25% of the predetermined amount of local anesthetic in case an injection fails or if supplemental anesthesia is needed later.5 With a reported 15%-20% failure rate for inferior alveolar nerve blocks, it is critical to use the proper technique in order to reduce the need for supplemental injections.2,22 On average, a child’s mandibular foramen is near the occlusal plane; by adulthood, the mandibular foramen moves posteriorly and is approximately 7 mm above the occlusal plane.2,23 Therefore, if the inferior alveolar nerve block is missed in the treatment of a child but the MRD has not been exceeded, one can attempt to inject vertically higher.2 While lip numbness is usually considered a sign of an adequate inferior alveolar nerve block, the lack of gingival response to stimulation is considered to be a more rapid and reliable indicator of anesthesia in young children than asking the patient about the presence or absence of lip numbness.2,24 A possible alternative to mandibular blocks for procedures in young children is to utilize a buccal mandibular infiltration technique with 4% articaine plus 1:100,000 epinephrine, which appears to produce a high success rate of mandibular pulpal anesthesia.25,26 If the injections fail and the predetermined maximum amount of local anesthetic has been administered, it is recommended to not attempt to supplement with more local anesthetic.2,22 The best approach would be to reschedule the treatment appointment. Local anesthetic systemic toxicity: warning signs and management When providing emergency care, a dentist needs to immediately recognize signs and symptoms of LAST (such as tremors or convulsions). The dental procedure should be stopped as soon as any neurological, respiratory, or cardiovascular signs or symptoms of local anesthetic overdose become apparent.5 The dentist should monitor vital signs (such as pulse and blood pressure), watch for coloration if pulse oximetry is not available, and assess breathing by looking for chest rise and movement of air. If necessary, initiate basic life support in the form of chest compressions and positive pressure ventilation with oxygen until medical assistance arrives.5 In the event of an emergency, any delay may result in the patient’s reserves of oxygen being consumed leading to poor oxygenation of key organs such as the brain and heart, and irreversible damage may occur. Three key interventions are necessary: 1) clear the airway of any obstructions including the tongue or foreign bodies such as gauze; 2) provide supplemental positive pressure oxygen; and 3) if the www.agd.org patient has no pulse, apply chest compressions so that oxygenated blood can reach the brain and heart.4 Basic life support skills are essential until the patient can be transferred to a hospital.4 Someone on the dental team should call for medical assistance; another should manage seizures and respiratory depression.5 The patient should be positioned on the left lateral side to facilitate suction, which should be applied to the pharynx to remove any saliva and foreign bodies, such as dislodged stainless steel crowns, rubber dam clamps, or pieces of gauze. An oxygen tank should be available to provide supplemental oxygen either by nasal cannula or nasal hood for a patient who is able to breathe, or by a bag-valve-mask if there is significant respiratory depression. According to Moore, “positive pressure oxygen ventilation is the most important element in managing local anesthetic overdose.”5 Although rarely required, advanced management of seizures may include the intravenous administration of a benzodiazepine such as diazepam or midazolam.5,12 Following any convulsion, serious respiratory depression can occur, so it is critical to continue to monitor the patient and support the airway.5,12 Conclusions While local anesthetics possess a wide margin of safety in adult patients, MRDs of these drugs can be easily exceeded in pediatric dental patients. The prevention of LAST in young children is best achieved by strictly adhering to weightbased MRD dosing guidelines. The more conservative Rule of 25, which states that no more than 1 cartridge of local anesthetic should be given for each 25 lb of patient body weight, will impart an added safety layer in children ≤8 years of age. General Dentistry January/February 2015 51 Anesthesia and Pain Control Local anesthetic calculations: avoiding trouble with pediatric patients Author information Dr. Saraghi is in private practice in New York, New York. Dr. Moore is a professor of Dental Anesthesiology, Pharmacology, and Public Health, University of Pittsburg School of Dental Medicine, Philadelphia. Dr. Hersh is a professor of Pharmacology, Department of Oral and Maxillofacial Surgery and Pharmacology, and the director of the Division of Pharmacology, University of Pennsylvania School of Dental Medicine, Philadelphia. References 1. Personal communication with Paul Mondock, senior vice president, Sales and Marketing, Septodont, Inc. June 7, 2013. 2. Cheatham BD, Primosch RE, Courts FJ. A survey of local anesthetic usage in pediatric patients by Florida dentists. ASDC J Dent Child. 1992;59(6):401-407. 3. Hersh EV, Helpin ML, Evans OB. Local anesthetic mortality: report of case. ASDC J Dent Child. 1991;58(6): 489-491. 4. Tarsitano JJ. Children, drugs, and local anesthesia. J Am Dent Assoc. 1965;70:1153-1158. 5. Moore PA. Preventing local anesthesia toxicity. J Am Dent Assoc. 1992;123(9):60-64. 6. Goodson JM, Moore PA. Life-threatening reactions after pedodontic sedation: an assessment of narcotic, local anesthetic, and antiemetic drug interaction. J Am Dent Assoc. 1983;107(2):239-245. 7. McAuliffe MS, Hartshorn EA. Anesthetic drug interactions. Quarterly update. CRNA. 1998;9(4):172-176. 8. Kohli K, Ngan P, Crout R, Linscott CC. A survey of local and topical anesthesia use by pediatric dentists in the United States. Pediatr Dent. 2001;23(3):265-269. 9. Zinman EJ. Letter: toxicity and mepivacaine. J Am Dent Assoc. 92(5):858. 10. Zinman EJ. More on mepivacaine. J Calif Dent Assoc. 1976;4(4):50. 11.Hersh EV, Hermann DG, Lamp CJ, Johnson PD, MacAfee KA. Assessing the duration of mandibular soft tissue anesthesia. J Am Dent Assoc. 1995;126(11): 1531-1536. 12. Moore PA, Hersh EV. Local anesthetics: pharmacology and toxicity. Dent Clin North Am. 2010;54(4):587-599. 13. Fonseca RJ. Oral and Maxillofacial Surgery. Vol 1. 1st ed. Philadelphia: W.B. Saunders Company; 2000. 14. Malamed SF. Morbidity, mortality, and local anesthesia. Prim Dent Care. 1999;6(1):11-15. 15. Meechan J. How to avoid local toxicity. Br Dent J. 1998;184(7):334-335. 16. Berquist HC. The danger of mepivacaine 3% toxicity in children. Can Dent Assoc J. 1975;3:13. 17. Zinman EJ. Letter: Toxicity and mepivacaine. J Am Dent Assoc. 1976;92(5):858. 18. Novocol Pharmaceutical of Canada, Inc. Octocaine (Lidocaine HCl 2% and Epinephrine 1:100,000 Injection) [package insert]. Available at: http://staging.test. novocol.com/docs/product-insert/Octocaine.pdf. Accessed October 8, 2014. AGDPODCAST Computer-Controlled Anesthesia 52 January/February 2015 General Dentistry www.agd.org 19. Novocol Pharmaceutical of Canada, Inc. Isocaine (Mepivacaine 3% Injection) [package insert]. Available at: http://www.novocol.com/our-products/injectableanesthetics/isocaine/. Accessed October 8, 2014. 20. Goebel WM, Allen G, Randall F. The effect of commercial vasoconstrictor preparations on the circulating venous serum level of mepivacaine and lidocaine. J Oral Med. 1980;35(4):91-96. 21. Goebel WM, Allen G, Randall F. Comparative circulatory serum levels of 2 per cent mepivacaine and 2 per cent lignocaine. Br Dent J. 1980;148(11-12):261-264. 22. Meechan J. How to avoid local anaesthetic toxicity. Br Dent J. 1998;184(7):334-335. 23. Berberich G, Reader A, Drum M, Nusstein J, Beck M. A prospective, randomized, double-blind comparison of the anesthetic efficacy of two percent lidocaine with 1:100,000 and 1:50,000 epinephrine and three percent mepivacaine in the intraoral, infraorbital nerve block. J Endod. 2009;35(11):1498-1504. 24. Ellis RK, Berg JH, Raj PP. Subjective signs of efficacious inferior alveolar nerve block in children. ASDC J Dent Child. 1990;57(5):361-365. 25. Robertson D, Nusstein J, Reader A, Beck M, McCartney M. The anesthetic efficacy of articaine in buccal infiltration of mandibular posterior teeth. J Am Dent Assoc. 2007;138(8):1104-1112. 26. Haase A, Reader A, Nusstein J, Beck M, Drum M. Comparing anesthetic efficacy of articaine versus lidocaine as a supplemental buccal infiltration of the mandibular first molar after an inferior alveolar nerve block. J Am Dent Assoc. 2008;139(9):1228-1235. Endodontics Exercise No. 362 Anesthesia and Pain Control Subject Code 132 The 15 questions for this exercise are based on the article, Local anesthetic calculations: avoiding trouble with pediatric patients, on pages 48-52. This exercise was developed by Riki Gottlieb, DMD, FAGD, in association with the General Dentistry SelfInstruction committee. 1. LAST can be described using all of the following terms except one. Which is the exception? A.rare consequence of LAO B. avoidable consequence of LAO C.allergic reaction to LAO D.occurs more frequently in children 2. According to the article, the most common cause of morbidity and mortality due to LAST is _______________________. A.respiratory depression B. cardiovascular stimulation C.central nervous system (CNS) excitation D.nerve damage 3. Symptoms of early toxicity consist of all of the following CNS symptoms except one. Which is the exception? A.metallic taste B.tinnitus C.dry mouth D.dizziness 4. Concomitant opioid sedative administration will _______ respiratory depression and ________ the seizure threshold of local anesthetics. A.reduce; increase B. enhance; increase C.reduce; decrease D.enhance; decrease 5. All of the following are relatively larger in children than adults except one. Which is the exception? A.tongue B.tonsil C.airway D.adenoid 6. A local anesthetic without a vasoconstrictor offers ______ minutes of pulpal anesthesia. A.20-40 B.60-80 C.100-120 D.140-160 Reading the article and successfully completing this exercise will enable you to: •describe the signs and symptoms of local anesthesia systemic toxicity (LAST); •understand the mechanism of action of local anesthetic toxicity (LAO); and •learn how to calculate the maximum recommended dose (MRD) to prevent local anesthesia toxicity. 7. Use of ______ makes it easier to reach or exceed the MRD. A.2% lidocaine, 1:100,000 epinephrine B. 3% mepivacaine, no epinephrine C.4% articaine,1:100,000 epinephrine D.5% bupivacaine, no epinephrine 8. A 4% formulation of a drug means that there are _____ mg/ml, and in a 1.8 ml dental cartridge there are _____ mg/ cartridge. A.30; 36 B. 30; 42 C.40; 54 D.40; 72 9. The MRD of 3% mepivacaine is 2.6 mg/ lb. What is the maximum number of cartridges one can give a 45 lb child? A.1 B.2 C.3 D.4 10. Clark’s rule is another weight-based method for calculating the MRD. According to Clark’s rule, the dose of local anesthetic should be reduced by the ratio of the child’s weight to an adult weight of 200 lb. A.Both statements are true. B. The first statement is true; the second is false. C.The first statement is false; the second is true. D.Both statements are false. 11. Using Clark’s rule, what would be a 60 lb child’s MRD for the use of 2% lidocaine with 1:100,000 epi? A.3.5 cartridges B. 4.5 cartridges C.5.5 cartridges D.6.5 cartridges 12. The effects of various local anesthetics used in conjunction with each other are unrelated. The effects of all local anesthetics, including toxicity, are mediated at the sodium channel in a dose-dependent fashion. A.Both statements are true. B. The first statement is true; the second is false. C.The first statement is false; the second is true. D.Both statements are false. 13. All of the following are correct about the Rule of 25 except one. Which is the exception? A.It can be applied to all US dental local anesthetic formulations for healthy patients. B. The Rule of 25 states that 1 cartridge of any formulation marketed in the US may be used per 25 lb. C.Using the Rule of 25 may be more appropriate in children ≤8 years than weight-based calculations. D.The Rule of 25 indicates the use of 3 cartridges of local anesthetic for a 50 lb child. 14. To prevent local anesthetic overdose, all of the following should be followed except one. Which is the exception? A.Determine the maximum amount of local anesthetic at the beginning of the appointment. B. Keep all used local anesthetic cartridges until the end of the appointment. C.Inject the local anesthetic quickly, at a rate of approximately 10-15 seconds per cartridge. D.Use aspiration technique to determine intravascular injection. 15. All of the following actions are to be performed immediately in the event of local anesthetic overdose, except one. Which is the exception? A.stop dental procedure B. administer nitrous oxide C.position patient on left lateral side D.begin basic life support and call 911 Answer form is on the inside back cover. Answers for this exercise must be received by December 31, 2015. www.agd.org General Dentistry January/February 2015 53 Forensic Dentistry The role of the dentist in identifying missing and unidentified persons Amber D. Riley, RDH, MS The longer a person is missing, the more profound the need for dental records becomes. In 2013, there were >84,000 missing persons and >8,000 unidentified persons registered in the National Crime Information Center (NCIC) database. Tens of thousands of families are left without answers or closure, always maintaining hope that their relative will be located. Law enforcement needs the cooperation of organized dentistry to procure dental records, translate their findings, and upload them into the NCIC database A ny single event—be it a natural disaster, terrorism act, or mass transit accident—that produced thousands of fatalities and tens of thousands of missing persons would cause concerned citizens and outraged family members to descend upon Capitol Hill, demanding that law enforcement and the government take immediate action to answer questions and show what they are doing to bring justice to the victims and closure to the victims’ families. However, even in the absence of cataclysmic events, there are still people being reported missing and unidentified bodies being found every day. The statistics are staggering. According to the National Crime Information Center’s “NCIC Missing Person and Unidentified Person Statistics for cross-matching with unidentified person records created by medical examiner and coroner departments across the United States and Canada. Received: March 24, 2014 Revised: July 24, 2014 Accepted: September 17, 2014 for 2013,” there were >84,000 missing persons (MPs) and >8,000 unidentified persons (UPs) in the United States and Canada that year, leaving many families without closure for their missing loved ones.1 In response to these daily numbers of MPs and UPs, the US has set very high standards for the identification of our nation’s deceased. The scientifically supported methods of human identification are fingerprints, dental records, and DNA.2,3 Each method is accurate and each requires comparison analysis. When a person is reported missing, a series of actions takes place. The first is the filing of a missing person (MP) report. This report is a detailed intake of the MP’s information that will include not only basic Fig 1. An example of a National Crime Information Center $.M. report. 54 January/February 2015 Key words: missing persons, unidentified persons, HIPAA, dental records General Dentistry www.agd.org information—such as height and weight, eye and hair color, and where they were last seen—but will also include information that is not made available to the public in order to assist in law enforcement’s search and investigation. This information includes the names and addresses of the MP’s dentist and medical doctor, as well as any referral information, such as orthodontic or endodontic specialists. This information is used in order to retrieve the MP’s antemortem medical and dental records. When a person is reported as missing, it is not automatically assumed by law enforcement that the MP is deceased; the gathering of medical and dental data specific to the MP is a critical part of any investigation.2,3 A dentist (or auxiliary) who has been specially trained as Fig 2. Postmortem dental record creation. Fig 3. Picture of a decedent’s hand showing unusable fingerprints due to decomposition in water. Fig 5. A decedent’s head with fourth degree postmortem burns, still showing the preserved dental evidence. a dental coder by the Federal Bureau of Investigation (FBI) translates the dental data into the NCIC system in order to cross-reference on a continual basis all unidentified bodies found in the US and Canada that have been entered into the system.1 Possible matches are marked, and daily reports of any “hits” are generated and remitted to the originating agencies (such as local police departments, county sheriffs, or highway patrol) that initially filed the MP reports.1 These reports are called $.M. reports (Fig. 1). Fig 4. Facial photograph of a decedent’s head showing how despite surrounding tissue decomposition, the dental evidence is preserved. The reports are then reviewed by the originating agency for their actual relevance to the case. If dental records need to be reviewed, it will be done by an FBI-trained dental coder, who will determine if the cross-match is valid and therefore requires a follow-up by the originating agency. When a body is recovered and the identity of the decedent is unknown, a postmortem dental record will be created as part of the autopsy (Fig. 2). This record will contain radiographs, photographs, and an odontogram. For a UP, the data will be coded and uploaded into the NCIC system for constant crossreferencing with all MP reports. It is from these UP files that the originating agencies investigating MPs get some of their hits. There is a national repository of radiographic and photographic images that can be accessed by authorized personnel for rapid record comparison when a strong hit from a $.M. report is received. Every dental professional understands how incredibly resistant to destruction the human dentition is. From a forensic standpoint, human teeth can withstand blunt force trauma; fires at profoundly high temperatures; natural decomposition; chemical erosions that destroy other tissues; and various environmental changes in climate, humidity, and exposure.2,3 Human skin begins to decompose www.agd.org immediately after death, and usable friction ridges (fingerprints) may rapidly deteriorate if the body is outdoors and certainly if the body is in water for several hours to a few days (Fig. 3 and 4).2,3 If the body (including the hands) has fourth or fifth degree burns, fingerprints will not be retrievable, and the recovery of usable DNA is highly compromised due to heat-related denaturation of proteins in the body.2,3 What will remain usable for identification in all of these scenarios are the decedent’s teeth (Fig. 5). The role of the dentist in helping law enforcement identify MPs or UPs involves both recordkeeping and the retention of records. The American Dental Association recommends full dental record retention of active and inactive patients, as well as keeping the record of a deceased patient for 2 years beyond their death.4 However, this is only a recommendation. There are many states in the US and provinces in Canada that have no minimum standard set for dental record retention whatsoever (although there are some exceptions for the records of children and the disabled). Death investigations have been severely compromised due to the destruction of patients’ dental records. Loss of dental records can be caused by overstringent housekeeping in the dental office—especially with inactive patients—or during changes in ownership of the practice when General Dentistry January/February 2015 55 Forensic Dentistry The role of the dentist in identifying missing and unidentified persons a new owner may purge old records. The problem of dental record destruction has become such a profound obstacle in the endeavor to find MPs and identify UPs that the American Society of Forensic Odontology (ASFO) published an official position paper on record retention directed toward general dentistry practitioners.5 The guidelines in this paper state that if, for good reason, a full record of a patient cannot be retained, then the dentist should retain—at a minimum—the most recent bitewing, full mouth, or panoramic X-rays for patients who have been inactivated, as well as a patient information form that includes the patient’s date of birth and social security or driver’s license number.5 If a photo of the patient is available, the dentist is advised to keep that, as well.5 If file space is at a premium, as it is in many dental offices even though practices are moving toward fully digitized record keeping, the aforementioned files can be scanned and saved onto an external drive to free up needed physical space. Taking this step not only maintains a record in case it is ever requested by law enforcement, it also allows the general dentist to organize and prioritize records for day-today practice. To address questions that a dentist may have about patient privacy and the legal ramifications for releasing a dental record without a patient’s permission, the Health Insurance Portability and Accountability Act (HIPAA) has a specific provision for this very scenario. This is stated in 45 CFR Section 164.512(g)(1), which reads in part: A covered entity (e.g., a hospital or doctor) may disclose protected health information to a coroner or medical examiner for the purpose of identifying a deceased person, determining a cause of death, or other duties as authorized by law.6 Dentists and their practices are indemnified from violation if they relinquish records to a law enforcement agent. A dentist will be given a written request on official letterhead of the law enforcement agency that contains the name of the patient, the case number of the investigation, and the name and contact information of the requesting agency and requesting officer (Fig. 6). A dentist should make duplicates of everything 56 January/February 2015 Fig 6. Sample record request from the Department of the Medical Examiner, San Diego, CA. in their patient’s record and give the entire original record to the investigator. Making a duplicate of the entire record is very important since the original record will likely be retained by the authorities, logged as evidence, and retained with the case material. A warrant is not needed for a dentist to release records to assist in an investigation. However, if a dentist chooses not to release dental records, a warrant will be issued, and the requested record will be legally confiscated in order to collect the needed information. As such, it is advisable to cooperate with law enforcement. Law enforcement agencies not only need dental records, they also need experienced dental professionals trained by the FBI as dental coders. A dental coder can directly create the postmortem dental records for the cases that enter the NCIC system from their assigned jurisdictions.1 General Dentistry www.agd.org The author of this article serves as a forensic dental autopsy technician. As an FBI-trained dental coder, the author is extremely aware of the importance of dental records in identifying UPs and MPs. No dental record is ever purged in the author’s office, radiographs are current and properly exposed, dental charting (digital) is updated to include existing as well as completed dentistry, and therapy records are detailed to include not only the procedure performed, but also the materials used in the treatment. Numerous intraoral and extraoral photographs are collected; these images are strongly recommended not just from a forensic standpoint (such as unusual tori or tooth anomalies), but also from the standpoint of impairing any illegitimate attempts of civil litigation against a dental practice—a dentist should take many photos, and take them often (Fig. 7 and 8). of human identification. A dentist’s responsibility to his/her patients does not end when records are archived. For the thousands of UPs, and the tens of thousands of MPs, the dental profession is obligated to retain the integrity of their dental records. Author information Fig 7. A sample photograph from a patient’s file showing unique and clinically significant intraoral anatomy (large, lobulated maxillary torus). Fig 8. A sample photograph from a patient’s file showing unique dental anatomy (accessory cusp on the buccal of tooth No. 2). Ms. Riley is a registered dental hygienist, San Diego, California. She is a member of the American Academy of Forensic Sciences, the American Society of Forensic Odontology, the American Dental Hygienists’ Association, the California Dental Identification Team, and the Disaster Mortuary Operational Response Team. Acknowledgments A general dentist can contribute to the effort of identifying the thousands of MPs and UPs reported across the US and Canada. The first step is to stop destroying dental records. There is always a possibility that a patient has become inactive because they are missing or deceased. The colder an MP case becomes, the more important that person’s dental record becomes, since teeth withstand the processes of decomposition and elemental exposure long after other sources of identification have disappeared.2,3 For a general dentist who is selling their practice, a provision can be added that the new owner must retain at least the minimal patient records—as outlined by the ASFO—of the old practice.5 At least once (and often twice) a year, the FBI will fund 2-day training workshops on NCIC coding for dentists and auxiliaries.1,7 Space is extremely limited, and positions are filled on a first-come, first-served registration basis. After the successful completion of this course, a dentist may be asked by his/her local or state bureaus to translate procured dental records for entry into the NCIC system, or to create postmortem records for UPs.7 The National Missing and Unidentified Persons System (NamUs) has a website on which anyone can view MP and UP reports which have been entered by law enforcement agencies.7,8 The NamUs site is managed by the US Department of Justice and was designed explicitly to solicit the public’s help in solving cases.8 There is access to names, filtered search results by state and city, and information on how to contact the investigator managing a specific case.7,8 Unlike televised depictions of forensic technologies that routinely locate evidence such as usable DNA samples from objects found at crime scenes or fingerprints from rough textiles, complex cases in real life are not quickly solved. The reality is that it takes teamwork and cooperation between law enforcement, healthcare providers, the public, and families of the missing to help identify and, if possible, bring home MPs and UPs. The identification of MPs and UPs aids in investigations that will hopefully provide answers as well as a sense of closure, and in some cases, mete out justice to the person or persons responsible for a victim’s demise. Conclusion Dentists should consider record retention as their professional duty. The dental profession serves as custodians of one of the most reliable, cost-effective, expedient, and scientifically supported methods www.agd.org The author would like to acknowledge Gary Bell, DDS, DABFO, Anthony Cardoza, DDS, DABFO, Stephanie Kavanaugh, DDS, DABFO, Craig Nelson, MD, American Academy of Forensic Sciences, American Board of Forensic Odontology, and the American Society of Forensic Odontology. References 1. National Crime Information Center. NCIC Missing Person and Unidentified Person Statistics for 2013. Available at http://www.fbi.gov/about-us/cjis/ncic/ ncic-missing-person-and-unidentified-personstatistics-for-2013. Accessed November 14, 2014. 2. Senn DR, Weems RA, eds. Manual of Forensic Odontology. 5th ed. Boca Raton, FL: CRC Press; 201:78-81. 3. Senn DR, Stimson PG. Forensic Dentistry, 2nd ed. Boca Raton, FL: CRC Press; 2010:163-183. 4. American Dental Association. Dental Records. Available at: http://raedentalmanagement.com/wp-content/ uploads/2014/03/ADA-Dental-Records.pdf. Accessed November 14, 2014. 5. American Society of Forensic Odontology. ASFO Dental Record Retention Position Paper. Available at: http:// asfo.org/asfo-dental-record-retention-position-paper/. Accessed November 7, 2014. 6. U.S. Department of Health and Human Services Office for Civil Rights. HIPAA Administrative Simplification, Regulation Text 45 CFR Parts 160, 162, and 164. Available at: http://www.hhs.gov/ocr/privacy/hipaa/ administrative/privacyrule/adminsimpregtext.pdf. Accessed November 7, 2014. 7. Silver WE, Souviron RR. Dental Autopsy. Boca Raton, FL: CRC Press; 2009:125-126. 8. US Department of Justice. National Missing and Unidentified Persons System (NamUs). Available at: http://www.namus.gov/. Accessed November 10, 2014. General Dentistry January/February 2015 57 Non-Surgical Endodontics Nonsurgical endodontic treatment of permanent maxillary incisors with immature apex and a large periapical lesion: a case report Gautam P. Badole, MDS n M.M. Warhadpande, MDS n Rakesh N. Bahadure, MDS n Shital G. Badole, BDS Immature teeth with necrotic pulp and large periapical lesions are difficult to treat via conventional endodontic therapy. However, they can be treated with calcium hydroxide and mineral trioxide aggregate (MTA). This article reports the case of a nonvital tooth with a periapical lesion and an open apex that was treated with a single-visit MTA apical plug. A radiographic evaluation taken 6 months S uccessful endodontic treatment requires cleaning and shaping to obtain a fluid-tight seal in apical areas.1 When teeth have incompletely formed apices (known as blunderbuss canals) and/or a root canal with abnormal apical constriction, it is difficult to control the obturating material within the canal during condensation.2,3 Apexification with calcium hydroxide [Ca(OH)2] has been the treatment of choice for necrotic teeth with open apices in recent years.3,4 Ca(OH)2 can be used alone or mixed with camphorated monochlorophenol (CMCP), metacresyl acetate (with or without CMCP), physiologic saline, Ringer’s solution, distilled January/February 2015 Key words: MTA, open apex, periapical lesion water, or an anesthetic solution.5 The usual time required to form a calcific barrier is 6-24 months.5 Determining the extent of apical closure can be difficult, as analyzing a 3-dimensional apical closure via a 2-dimensional radiograph can lead to misinterpretation.6 The disadvantages of long-term use of Ca(OH)2 include the need for multiple appointments, possible recontamination of the root canal, and increased brittleness of the root dentin.7,8 A 1975 study by Roberts & Brilliant reported the use of tricalcium phosphate as an apical barrier.9 Mineral trioxide aggregate (MTA) was developed as a root-end filling material. Apexification using MTA has several advantages, as it is not resorbed, it Fig. 1. A preoperative radiograph showing open apices on teeth No. 8 and 9, with a large periapical lesion extending across teeth No. 7 and 8. 58 post-treatment showed a decrease in the periapical lesion; at 1 year, complete healing was visible. Received: October 21, 2013 Accepted: November 24, 2013 General Dentistry does not weaken the root canal dentin, and it sets in a wet environment. Satisfactory compaction of filling material can be achieved as MTA forms a hard and nonresorbable apical barrier.10 MTA also is used for single-step apexification in open apex cases, producing less inflammatory reactions in the periapical area and favoring bone formation. This case report used the MTA apical plug technique for successful nonsurgical management of a tooth with a large periapical lesion and blunderbuss canal. Case report A 24-year-old woman complained of mild, intermittent pain in the maxillary anterior region. Patient history revealed that she Fig. 2. A radiograph taken after placement of MTA apical plugs in teeth No. 8 and 9. www.agd.org Fig. 3. A radiograph of teeth No. 7, 8, and 9 taken postobturation. Discussion Fig. 4. A radiograph taken 6 months post-treatment. Note the decrease in size of the periapical lesion. Fig. 5. A radiograph taken 1 year post-treatment. Note that the periapical lesion is completely healed. had suffered a trauma 15 years earlier. Clinical examination showed loss of enamel translucency in teeth No. 7, 8, and 9. Tooth mobility within the physiologic limit was present. Teeth No. 7 and 9 demonstrated mild pain on percussion. A periapical radiograph revealed a large periapical lesion (5 x 5 cm) extending across teeth No. 7 and 8. The lesion showed a well-defined nonsclerotic border. Open apices were found in both teeth No. 8 and 9 (Fig. 1). Soft tissue examination showed that gingival and mucogingival tissue were normal. None of the teeth responded to electric and thermal pulp vitality tests. There was no history of discharge or swelling, and the patient’s medical history was noncontributory. Based on clinical and radiographic findings, a diagnosis of chronic apical periodontitis with immature apex was made for teeth No. 7, 8, and 9. A treatment plan was proposed involving root canal therapy for all 3 teeth, with an MTA apical plug for teeth No. 8 and 9. After rubber dam isolation, access cavities were prepared for the 3 teeth. Working length was established with both radiographic and electronic apex locators (Root ZX, J. Morita USA, Inc). Root canals were cleaned mechanically using H-files (DENTSPLY International) and gentle but copious irrigation with 0.5% sodium hypochlorite and saline. After drying the canals with paper points, Ca(OH)2 paste was placed into the root canal as an intracanal medicament. After placing a sterile cotton pellet, the access cavities were closed with cement (IRM, DENTSPLY International). One week later, the patient was asymptomatic and the Ca(OH)2 was removed. Root canals were irrigated with 0.5% sodium hypochlorite, 17% EDTA (Pulpdent Corporation), and a final rinse of 2% chlorhexidine gluconate. Canals were dried with paper points, and MTA (ProRoot MTA, DENSTPLY Tulsa) was placed in the apical portion of teeth No. 8 and 9. Subsequent increments were condensed with a hand plugger until a thickness of 4-5 mm was achieved (Fig. 2). A wet cotton pellet was placed into the canals and the access cavity was sealed with IRM. Using the lateral condensation technique, tooth No. 12 was obturated with gutta percha and root canal sealer (AH Plus, DENTSPLY Tulsa Dental Specialties) at the same appointment. On the following day, the remaining canals in teeth No. 8 and 9 were obturated by applying gutta percha with AH Plus and using the lateral condensation technique (Fig. 3). The access cavity was sealed with resin-modified glass ionomer cement (GC Fuji PLUS, GC America, Inc.). At a follow-up visit 6 months posttreatment, a radiograph revealed a marked decrease in the size of the periapical lesion (Fig. 4). At 1 year, the periapical radiolucency had healed completely (Fig. 5). www.agd.org The diagnosis of chronic apical periodontitis and immature apex was confirmed. A large periapical radiolucency was present, suggesting periapical granuloma or periapical/radicular cysts. Although there are histological differences between these conditions, they cannot be differentiated clinically as their clinical and radiographic appearances are identical. The borders of the radiolucency cannot be used as diagnostic criteria.11,12 It is now accepted that a well-defined border indicates a long-standing lesion that is slowly increasing in size, whereas a diffuse border is more likely to indicate a rapidly expanding lesion.13 The size of the radiolucency is irrelevant to the histological state of the tissue, as both small and large lesions could be granulomas, abscesses, or cysts. Since granulomas and radicular cysts are difficult to diagnose differentially, they are classified clinically by the general term chronic apical periodontitis.11-13 When performing root canal treatment in teeth with necrotic pulps and wide-open apices, the main challenge is obtaining an optimal apical seal. According to a 2005 prospective clinical study, Ca(OH)2 apexification therapy had a 100% success rate, with a mean of approximately 12 months to form an apical barrier.14 Disadvantages of Ca(OH)2 apexification include failure to control infection, recurrence of infection, and cervical fracture.15 Creating an MTA apical plug in a single visit has been suggested for nonvital immature permanent teeth as an alternative to long-term apexification treatment, offering good apical seal, biocompatibility, and pulpal and periodontal regenerating capabilities.16 MTA has the potential to provide an effective seal (even in the presence of blood and moisture) and form a primary monoblock.2 A 5 mm barrier is significantly stronger and demonstrates less leakage than a 2 mm barrier.17 The major problem in cases of a wideopen apex is the need to limit the material to the periapical area, thus avoiding the extrusion of a large amount of material into the periodontal tissue. A large volume of the extruded material may set before it disintegrates and is resorbed. This might result in the persistence of the inflammatory process, which may complicate General Dentistry January/February 2015 59 Non-Surgical Endodontics Nonsurgical endodontic treatment of permanent maxillary incisors repair of the tissue. The use of a matrix is advisable since its placement in the area of bone destruction provides a base for a sealing material (such as MTA). In cases of teeth with incomplete formation of apex, several materials have been recommended to create a matrix. These materials include calcium hydroxide, hydroxyapatite, resorbable collagen, and calcium sulfate.18-21 In the present case, the MTA plug technique was used successfully for the endodontic treatment of an open apex with a periapical lesion. Six- and 12-month follow-up radiographs showed complete healing for the apical lesion and the regeneration of periradicular tissues. Three hours after mixing, the pH of the MTA increased from 10 to 12.5. It is assumed that in a high pH environment, calcium ions that are released from MTA react with phosphates in the tissue fluid to form hydroxyapatite, which would explain its favorable sealing ability and biocompatibility.4,22 MTA stimulates interleukin production and cytokine release; it also promotes hard tissue formation.23 A 2009 cell culture study on human alveolar osteoblasts reported the expression of runt-related transcription factor 2 (which is essential for osteoblast differentiation and bone formation) in the presence of MTA mixed with either sterile water or an anesthetic solution.24 Studies have reported that MTA is both osteoconductive and osteoinductive; thus it favors bone formation.25-27 According to the literature, MTA showed the highest amount of hard tissue formation and the lowest level of periapical inflammation in open apex cases.28-29 The single-visit MTA apical plug technique saves time compared to Ca(OH)2 apexification, and offers predictable apical barriers that favor periapical tissue regeneration. Conclusion A single-visit MTA apical plug is an effective method to provide a good apical seal in open apex cases. It also offers the advantages of biocompatibility, predictability, less treatment time, and fewer appointments. Author information Dr. G. Badole is a lecturer, Department of Conservative Dentistry & Endodontics, 60 January/February 2015 VSPM’s Dental College and Research Center, Nagpur, India, where Dr. S. Badole is an intern. Dr. Warhadpande is an associate professor, Government Dental College and Hospital, Nagpur, India, where Dr. Bahadure is a lecturer, Department of Pedodontics. References 1. Ng YL, Mann V, Rahbaran S, Lewsey J, Gulabivala K. Outcome of primary root canal treatment: systematic review of the literature—part 2. Influence of clinical factors. Int Endod J. 2008;41(1):6-31. 2. Park JB, Lee JH. Use of mineral trioxide aggregate in the open apex of a maxillary first premolar. J Oral Sci. 2008;50(3):355-358. 3. Raldi DP, Mello I, Habitante SM, Lage-Marques JL, Coil J. Treatment options for teeth with open apices and apical periodontitis. J Can Dent Assoc. 2009;75(8): 591-596. 4. Huang GT. Apexification: the beginning of its end. Int Endod J. 2009;42(10):855-866. 5. Frank AL. Therapy for the divergent pulpless tooth by continued apical formation. J Am Dent Assoc. 1966; 72(1):87-93. 6. Rafter M. Apexification: a review. Dent Traumatol. 2005;21(1):1-8. 7. Asgary S, Ehsani S. MTA resorption and periradicular healing in an open-apex incisor: a case report. Saudi Dent J. 2012;24(1):55-59. 8. Sharma R, Dhingra A, Nayar R. Delayed MTA apical plug in immature open apex—a case report. Endodontol. 2008;20:49-52. 9. Roberts SC Jr, Brilliant JD. Tricalcium phosphate as an adjunct to apical closure in pulpless permanent teeth. J Endod. 1975;1(8):263-269. 10. Trope M. Treatment of immature teeth with non-vital pulps and apical periodontitis. Endod Topics. 2007; 14(1):51-59. 11.Ramachandran Nair PN, Pajarola G, Schroeder HE. Types and incidence of human periapical lesions obtained with extracted teeth. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 1996;81(1):93-102. 12. Ramachandran Nair PN. Apical periodontitis: a dynamic encounter between root canal infection and host response. Periodontol 2000. 1997;13:121-148. 13. Abbott PV. Classification, diagnosis and clinical manifestations of apical periodontitis. Endod Topics. 2004; 8(1):36-54. 14. Dominguez Reyes A, Munoz Munoz L, Aznar Martin T. Study of calcium hydroxide apexification in 26 young permanent incisors. Dent Traumatol. 2005;21(3):141145. 15. Maroto M, Barbería E, Planells P, Vera V. Treatment of a non-vital immature incisor with mineral trioxide aggregate (MTA). Dent Traumatol. 2003;19(3):165169. 16. Torabinejad M, Watson TF, Pitt Ford TR. Sealing ability of a mineral trioxide aggregate when used as a root end filling material. J Endod. 1993;19(12):591595. 17. Pelliccioni GA, Ciapetti G, Cenni E et al. Evaluation of osteoblast-like cell response to Proroot MTA (mineral General Dentistry www.agd.org trioxide aggregate) cement. J Mater Sci Mater Med. 2004;15(2):167-173. 18. Al-Daafas A, Al-Nazhan S. Histological evaluation of contaminated furcal perforation in dogs teeth repaired by MTA with or without internal matrix. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2007; 103(3):92-99. 19. Jantarat J, Dashper SG, Messer HH. Effect of matrix placement on furcation perforation repair. J Endod. 1999;25(3):192-196. 20. Bargholz C. Perforation repair with mineral trioxide aggregate: A modified matrix concept. Int Endod J. 2005;38(1):59-69. 21. Zou L, Liu J, Yin SH, Tan J, Wang FM, Li W, et al. Effect of placement of calcium sulphate when used for repair of furcation perforation on seal produced by a resin-based material. Int Endod J. 2007;40(2):100105. 22. Dogra S, Mukunda KS, Arun A, Rao SM. Apexification. J Dental Sci Res. 2012;3(1):1-4. 23. Tait CM, Ricketts DN, Higgins AJ. Weakened anterior roots-intraradicular rehabilitation. Br Dent J. 2005; 198(10):609-617. 24. Perinpanayagam H, Al-Rabeah E. Osteoblasts interact with MTA surfaces and express Runx2. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2009;107(4):590596. 25. Cintra LT, de Moraes IG, Estrada BP, et al. Evaluation of the tissue response to MTA and MBPC: microscopic analysis of implants in alveolar bone of rats. J Endod. 2006;32(6):556-559. 26. Moretton TR, Brown CE Jr, Legan JJ, Kafrawy AH. Tissue reactions after subcutaneous and intraosseous implantation of mineral trioxide aggregate and ethoxybenzoic acid cement. J Biomed Mater Res. 2000; 52(3):528-533. 27. Tani-Ishii, Hamada N, Watanabe K, Tujimoto Y, Teranaka T, Umemoto T. Expression of bone extracellular matrix proteins on osteoblast cells in the presence of mineral trioxide. J Endod. 2007;33(7): 836-839. 28. Ham KA, Witherspoon DE, Gutmann JL, Ravindranath S, Gait TC, Opperman LA. Preliminary evaluation of BMP-2 expression and histological characteristics during apexification with calcium hydroxide and mineral trioxide aggregate. J Endod. 2005;31(4):275-279. 29. Felippe WT, Felippe MC, Rocha MJ. The effect of mineral trioxide aggregate on the apexification and periapical healing of teeth with incomplete root formation. Int Endod J. 2006;39(1):2-9. Manufacturers DENTSPLY International, York, PA 800.877.0020, www.dentsply.com DENTSPLY Tulsa Dental Specialties, Tulsa, OK 800.662.1202, www.tulsadentalspecialties.com GC America, Inc., Alsip, IL 800.323.7063, www.gcamerica.com J. Morita USA, Inc., Irvine, CA 800.831.3222, www.morita.com/usa Pulpdent Corporation, Watertown, MA 800.343.4342, www.pulpdent.com Fixed Removable Hybrid Prosthesis Stress analysis of mandibular implant-retained overdenture with independent attachment system: effect of restoration space and attachment height Behnaz Ebadian, DDS, MSc n Saeid Talebi, MSc n Niloufar Khodaeian, DDS, MSc n Mahmoud Farzin, PhD In this in vitro study, 2 implants were embedded in the interforaminal region of an acrylic model. Two kinds of retention mechanisms were used to construct complete overdentures: ball type and direct abutment (Locator). The ball-type retention mechanism models included 3 different collar heights (1, 2, and 3 mm) with 15 mm occlusal plane height, and 3 different occlusal plane heights (9, 12, and 15 mm) with 1 mm collar height. The direct abutment models included 3 different occlusal plane heights (9, 12, and 15 mm) with 1 mm cuff height. Vertical unilateral and bilateral loads of 150 N were applied to the central fossa of the first molar. The stress of the bone around the implant was analyzed by finite element analysis. The results showed that by increasing vertical restorative space, the maximum stress values around implants were decreased in both unilateral and bilateral loading models. The results also showed that the increase T he restoration of an edentulous mandible with an overdenture supported or retained by 2 implants is considered to be the primary prosthetic treatment approach.1 The retention and stability of prostheses are provided primarily by implants through attachments.2,3 Various types of attachments have been suggested for implant-supported overdentures. Independent or dependent connection of implants through ball, O-ring, Locator, and bar attachments are the most common approaches.2-5 Some studies have reported implant support via ball-type attachments as a reliable treatment.3,6-10 The freedom of rotation within the ball attachment allows for stress release. The method of retaining overdentures by 1 or 2 implants using resilient attachments is a relatively simple and inexpensive method to reconstruct an edentulous mandible.11 Selection of the optimal attachment is dependent upon the required retention, jaw morphology and anatomy, oral function, and patient compliance for recall.12 The ball attachment places less stress on implants and produces less bending movement in comparison to the bar-clip attachment.3 The Locator, which is self-aligning and has dual retention, is another type of independent attachment. It is available in in maximum stress values around implants correlated with the ball attachment collar height. The Locator attachment with a 1 mm cuff height and 9 mm occlusal plane height demonstrated 6.147 and 3.914 MPa in unilateral and bilateral loading conditions, respectively. While a reduction in the collar height of a ball-type retention mechanism and an increase in the vertical restorative space in direct abutment retention mechanisms are both biomechanically favorable, and may result in reduced stress in periimplant bone, a ball attachment seems to be more favorable in the stress distribution around an implant than a Locator attachment. Received: April 11, 2013 Accepted: July 10, 2013 Key words: overdenture, stress, finite element analysis, independent attachment, occlusal plane various vertical heights, and its resiliency, retention, and durability are favorable.12 The effect of a resilient or rigid attachment system on retention and stress distribution is a subject of controversy in the literature.12-16 Biomechanically, the advantages of implant splinting are unclear. The rationale of implant splinting was that it would decrease stresses due to increased prosthesis stability.17,18 Adequate restorative space is another important factor in successful implantretained overdenture treatment.19 In edentulous patients, available restorative space is bounded by the supporting tissues of the edentulous jaw, cheeks, lips, tongue, and the occlusal plane. Other factors must also be considered when defining available restorative space, such as interocclusal distance, phonetics, and esthetics.20 The minimum vertical restorative space required for an implant-supported overdenture is 8.5 mm for Locator attachments, 10-12 mm for ball and O-ring attachments, and 13-14 mm for bar-clip attachments.20 The distance from the crest of the alveolar bone to the plane of occlusion in implant-supported prostheses is defined as the crown height space (CHS). The biomechanics of CHS is related to lever arm mechanics.21 Nonaxial loading creates www.agd.org a lateral moment which proportionally increases with increased CHS; this results in stress concentration at the bone surrounding the implant neck.22 Increasing the CHS by 1 mm results in a 20% increase in the cervical load on a fixed-implant prosthesis. Implant splinting has been suggested to overcome the biomechanical overload in this situation. However, implant splinting in fixed-implant supported prostheses has not been proven to significantly improve implant success rates.23 Fabricating an implant-supported overdenture requires an adequate space for restorative components.19 Evaluation of space limitation after implant surgery allows for appropriate attachment selection. Inappropriate treatment planning before placing a removable implant-supported prosthesis can lead to problems such as overcontoured or fractured prostheses. Two height levels should be considered in any removable prosthesis with mobility and soft tissue support: the first is the height of the attachment system to the crest of the bone, and the second is the distance from the attachment to the occlusal plane.21 In a finite element analysis (FEA) study, Ebadian et al evaluated different vertical restorative spaces and different bar heights of mandibular overdentures, and showed General Dentistry January/February 2015 61 Fixed Removable Hybrid Prosthesis Stress analysis of mandibular implant-retained overdenture attachments Overdenture Metal housing Metal housing Plastic cap Plastic cap Ball abutment Locator abutment Implant Mandible Fig. 1. Computerized mesh modeling showing jaw and overdenture with ball attachment.24 Implant Fig. 2. Computerized mesh modeling showing Locator system.24 Fig. 3. Modeling of 3 different occlusal plane heights.24 that increasing the vertical restorative space and decreasing the bar height led to a decrease in the maximum stress value around the implants when a unilateral load was applied.24 Since the use of independent attachments in different occlusal plane heights is not well-defined, the purpose of this study was to evaluate the effect of different vertical restorative spaces (that is, occlusal plane distance to gingival level) and different ball attachment collar heights on the stress distribution around implants by 3-dimensional (3D) finite element analysis. Materials and methods In this in vitro study, the experimental design included the fabrication of a simulated 2-implant-retained mandibular overdenture. For this purpose, an acrylic model of an edentulous mandible was fabricated with a clear acrylic resin (Meliodent Multicryl, Heraeus Kulzer). The configuration of the bone was duplicated from an edentulous mandibular skeleton. Two screw-type implants, 4 x 10.5 mm with a 4.5-mm-diameter 62 January/February 2015 abutment platform (Biohorizons Internal, BioHorizons IPH, Inc.), were embedded in the interforaminal region of the acrylic model using a surveyor (Ney Surveyor, DENTSPLY International). The implants were vertically oriented, perpendicular to the occlusal plane, and parallel to each other. The crestal bone position of the implants was on the top of the ridge. The interimplant distance was 20 mm. Two types of retention mechanisms were used in this study: a ball attachment with plastic matrix and metal housing (BioHorizons IPH, Inc.), and a direct abutment attachment with plastic matrix and metal housing (Locator attachments, 4.5 mm with a 1.0 mm cuff, BioHorizons IPH, Inc.) (Fig. 1 and 2).24 Based on the laboratory design used by Ebadian et al, a complete overdenture was fabricated on these attachment models.24 The plastic model, acrylic denture, implants, Locator and ball attachments were used for computerized reproduction. To improve analysis, the implants were considered as flat cylinders. The 3D geometry of the entire system was scanned and digitized using General Dentistry www.agd.org ATOS II (Triple Scan) scanning technology (GOM mbH) and viewer software (ATOS version 6.3.0, GOM mbH). Implants were assumed to be completely osseointegrated, so that a mechanically perfect interface—to ensure the continuity of displacement and traction vectors—was pressured between implants and bone. Other contacts existing between the elements were also assumed to be perfect. The resultant dense point cloud was transferred to CATIA modeling software (Dassault Systemes Americas Corp.). The geometry was then meshed by tetrahedral linear elements. The mucosa and cortical bone were reproduced as a 2 mm and 2.5 mm layer, respectively. Three different collar heights (1, 2, and 3 mm) with a 15 mm occlusal plane height, and 3 different occlusal plane heights (9, 12, and 15 mm) with a 1 mm collar height were modeled for the ball attachment system (Fig. 3). Three different occlusal plane heights (9, 12, and 15 mm) with a 1 mm cuff height were modeled for the Locator system. Thus, 9 models were obtained. The value of friction coefficient was fixed to 0.02.25 Table 1. Mechanical properties of the prosthesis, implant, and bone materials used in this study.13,27-30 Table 2. The number of elements and nodes in the ball attachment models. Young modulus (Pa) Poisson ratio Cortical bone 1.37×1010 0.30 Trabecular bone 1.37×109 0.30 Mucosa 1.0×107 0.40 Acrylic resin 2.7×109 0.35 Titanium 1.17×1011 0.33 Gold 1.0×10 0.30 5×10 0.45 Material Rubber 11 6 Occlusal Collar plane height height (mm) (mm) Number of elements Number of nodes 9 1 147,640 40,898 12 1 155,058 42,095 15 1 161,329 43,240 15 2 164,140 43,828 15 3 166,287 44,355 Table 3. The number of elements and nodes in the Locator attachment models. Occlusal Cuff plane height height (mm) (mm) Number of elements Number of nodes 9 1 176,967 50,772 12 1 184,234 51,957 15 1 190,533 53,181 Table 4. Stress values generated in the bone in the ball attachment model with different occlusal plane and collar heights by unilateral and bilateral loading. Occlusal plane height (mm) Distal side force (MPa) Mesial side force (MPa) Maximum force (MPa) Collar height (mm) Unilateral Bilateral Unilateral Bilateral Unilateral Bilateral 9 1 5.249 2.811 4.224 0.870 5.249 3.263 12 1 4.695 2.557 3.685 0.754 4.695 3.365 15 1 4.438 2.455 3.407 0.726 4.438 3.428 15 2 4.920 2.429 3.863 0.722 4.920 3.443 15 3 5.357 2.493 4.262 0.751 5.357 3.439 Table 5. Stress values generated in the bone in the Locator attachment models with different occlusal plane heights by unilateral and bilateral loading. Occlusal plane height (mm) Distal side force (MPa) Mesial side force (MPa) Maximum force (MPa) Cuff height (mm) Unilateral Bilateral Unilateral Bilateral Unilateral Bilateral 9 1 6.147 3.914 4.143 1.063 6.147 3.914 12 1 5.702 3.450 3.823 1.008 5.702 3.450 15 1 5.378 3.103 3.606 0.855 5.378 3.422 Stress analysis was performed using FEA software (ABAQUS version 6.11, Abaqus, Inc.). Linear static analysis was used in this study. Arbitrary 150 N vertical unilateral and bilateral loads representing the masticatory force were applied to the central occlusal fossa of the first molar of the prosthesis.26 Mechancial properties for the prosthesis and all implant parts and bone are shown in Table 1.13,27-30 The number of elements and nodes are summarized in Tables 2 and 3. Results Maximum stress values on the bone in the bilateral and unilateral loading models of ball attachment and Locator systems are shown in Tables 4 and 5. www.agd.org Maximum stresses were found in the Locator model with 1 mm cuff height and 9 mm occlusal plane height. The stresses were 6.147 and 3.914 MPa in unilateral and bilateral loading conditions, respectively. In the ball attachment models, maximum stress values of bone were observed mostly in the distal bone adjacent to the General Dentistry January/February 2015 63 Fixed Removable Hybrid Prosthesis Stress analysis of mandibular implant-retained overdenture attachments Fig. 4. Stress distribution pattern in ball attachment model when load applied. Top. Unilateral. Bottom. Bilateral.24 ipsilateral implant when a unilateral load was applied, and more distal to the bone adjacent to the implants when a bilateral load was applied (Fig. 4). The maximum stresses in the Locator attachment system were observed in the distal side of the ipsilateral implant when unilateral and bilateral loads were applied (Fig. 5).24 Discussion Dependent and independent attachment systems have been used in implant-supported overdentures. Many researchers have evaluated either ball or bar-clip attachment systems in overdentures.8,31-34 The present study evaluated stress distributions of an overdenture retained by either a ball attachment or Locator system on 2 implants in a mandibular jaw model. Various occlusal plane heights were studied in these models. The selection and application of different attachment systems for implant overdentures depend on many factors, such as retention, stress, restorative space, and maintenance.3,20 Fractures of implants, attachments and prostheses can occur due to biomechanical stresses. Misch showed how stress management in implant prostheses is important in order to reduce fracture rates.35 64 January/February 2015 Fig. 5. Stress distribution pattern in Locator attachment model when load is applied. Top. Unilateral. Bottom. Bilateral.24 Comparisons of ball attachment vs barclip attachments have been conducted in other studies with varying results in terms of retention and maintenance.36,37 Kleis et al reported a higher rate of maintenance for Locator systems in comparison to ball attachments in mandibular 2-implant overdentures.38 Cakarer et al reported no difference between ball attachment and Locator systems regarding implant failure, replacement of attachments, and fracture of overdentures.11 However, they found that overall, the Locator system had more advantages than the ball or bar-clip systems.11 Celik & Uludag used a photoelastic model to evaluate the stress transfer of various types of attachments in a mandibular implant overdenture.39 They reported that the Locator system showed greater stresses as compared to ball, bar-clip, and bar-ball attachment systems.39 Kenney & Richards reported less stress was transferred to implants by a ball/O-ring attachment system than a barclip attachment.40 Tokuhisa et al compared the transferred stresses of O-ring/ball and bar-clip attachment systems and concluded that, the ball/O-ring system minimized the stress transferred to the bone surrounding implant-supported overdentures in comparison to the bar-clip system.3 General Dentistry www.agd.org Maximum stresses of ball and Locator attachments in unilateral loading models in this study were 4.438 and 5.378 MPa, respectively; and in bilateral loading conditions, the maximum stresses were 3.428 and 3.422 MPa, respectively. Ebadian et al found the maximum stresses of a barclip attachment system model—with 1 mm bar height and 15 mm occlusal plane height—were 4.753 and 3.482 MPa in unilateral and bilateral loading conditions, respectively.24 Comparing the result of these 2 studies showed that the Locator attachment transferred more stress than the bar clip, and the ball attachment transferred the least stress of all 3 attachment systems when a unilateral load was applied. In bilateral loading conditions, all 3 attachments transferred almost the same stress to the peri-implant bone.24 These findings are in agreement with previous studies that used unilateral loading.3,39,40 In the current study, the maximum stress was found in bone adjacent to the implant in unilateral loading models; however, in bilateral loading conditions, the maximum stress of the ball attachment was observed more distal from the bone adjacent to the implant than the Locator attachment. This may be due to the more rigid behavior of a Locator system, which restricts the movement of the overdenture and thus increases the stress in the bone around the implant while decreasing the stress in the posterior residual ridge. The maximum stress locations in these models were similar to the study by Ebadian et al which evaluated bar-clip attachments of mandibular overdentures.24 It is evident in Figures 4 and 5 that the stress distribution in the ball attachment model was more uniform than that of the Locator model, which was concentrated around the implants. The stress obtained from applying a mastication load both unilaterally and bilaterally is distributed into 2 segments: the posterior ridge and the bone around the implants, both of which are influenced by the retention mechanism of the attachment system. Therefore, whenever the attachment system is more resilient, the stress in the bone around the implant is subsequently lessened and a part of the stress is transferred to the posterior ridge; this results in better stress distribution and thus reduces the maximum stress level. The ball attachment is more resilient than the Locator system, thus it causes more uniform and less maximum stress. Resiliency in these 2 attachment systems is closely related to the plastic caps that are used. Therefore, because the plastic volume in the cap of a ball attachment is greater than the plastic volume in a Locator attachment, and because the ball attachment has a single retention mechanism while the Locator has dual retention, the ball attachment is more resilient and transfers less stress than the Locator system. Takeshita et al reported that the retentive forces of an attachment system affect stresses generated in the peri-implant bone during loading.41 This finding could explain why more stresses are generated in the bone by the Locator attachment in comparison with the ball attachment. The Locator system used in this study has a dual retention mechanism, therefore it is more retentive than the ball attachment. Chen et al observed that the least retentive attachments offer greater rotation than the more retentive ones.10 The authors compared Locator, ERA, and O-ring systems and reported that the O-ring system was the least retentive system.10 Their findings are in agreement with the present study. A meta-analyses study on mandibular overdentures by Cehreli et al reported no differences in marginal bone loss around implants in various attachment designs.42 The level of stress correlated to bone resorption has not been clearly defined in the literature.43 Since an FEA can only produce theoretical conclusions, the aim of this study was not to report absolute values of stresses but to compare stress values between different models.28,44 It is very important to choose the appropriate attachment system according to patient characterization in terms of bone quality and quantity, stress conditions, desired retention and stability, available restorative space, and patient maintenance. By increasing the occlusal plane height in this study from 9 to 15 mm, the maximum stress in the bone around the implant was decreased in the unilateral and bilateral loading models of the ball attachment and Locator systems, but the maximum stress in the posterior residual ridge was slightly increased in the bilateral loading models of ball attachments, which tolerated the maximum stress in these models. The study by Ebadian et al on bar-clip attachments showed the same results when a unilateral load was applied—the stress with a bilateral load slightly decreased when the occlusal plane height was increased.24 By increasing the collar height of the ball abutment from 1 to 3 mm, the maximum stress was increased. This was also in agreement with the study by Ebadian et al.24 Therefore, it can be concluded that by increasing the first lever arm (distance from crest of bone to attachment level), stresses in the bone around the implants increase. By increasing the second lever arm (distance of occlusal plane of denture to attachment), the stress values were decreased in both the Locator and ballattachment systems. According to Cehreli et al, when severe vertical bone loss is present, vertically cantilevered occlusal loading will increase.42 However, the results of the present study are not in agreement with that claim. This study found that increasing the occlusal plane height decreased the stress generated in bone, especially with the Locator attachment system. Increasing the collar height of abutment, or decreasing the second lever arm could result in increased stress. www.agd.org So it could be concluded that in abundant vertical space, even low height attachments are biomechanically advantageous. It has been recommended that a minimum of approximately 12 mm vertical restorative space is necessary to consider a mandibular implant-supported overdenture.45,46 The minimum space required for an implant-retained overdenture with a Locator system is 8.5 mm (vertical) x 9 mm (horizontal).47 Based on the authors’ findings and from a biomechanical and stress-generated aspect, in a restricted vertical space, ball attachments with minimum collar heights are preferred to Locator attachments. The roles of crown/implant ratio and CHS in fixed-implant prostheses are controversial in the literature.48-50 The role of CHS and its biomechanical effect is related to lever mechanics.51 A CHS ≥15 mm can be biomechanically unfavorable, resulting in increased stress at the bone around the implant.52 It appears that the CHS role in fixed-implant prostheses is not completely applicable in implant overdentures. Our findings indicate that by increasing the CHS (via occlusal plane height), the stress generated in the bone was decreased. This may be related to the different support, movement, and leverage mechanisms of the 2 tested prostheses. There are some unavoidable limitations in an FEA study, mainly in biologic simulations, which compelled the authors to assume some simplifications. Bone is a complex living structure without a defined pattern; its characteristics vary among individuals, and its actual mechanical properties are not precisely established. Furthermore, the use of FEA in a study of an extremely accurate anatomy of a bone structure may limit the results to that particular structure. As such, certain simplifications were adopted in this study to generalize the results and facilitate the study without compromising the validity of the findings. The implants were modeled without threads, as the aim of the study was to analyze the stresses on implants and not the mechanical interactions within the bone.28 It has been said that this assumption results in an underestimation of stress patterns in bone, as reported in previous studies.53,54 In addition, the connecting screws at the implantabutment interface were not modeled, General Dentistry January/February 2015 65 Fixed Removable Hybrid Prosthesis Stress analysis of mandibular implant-retained overdenture attachments although some studies have shown that modeling the screw is not necessary.28 It was assumed that the models were homogenous and isotropic. Because this study was comparative in nature, such assumptions would not interfere in the results, since they were present in all models.55 Conclusion Within the limitation of this study, it can be concluded that by decreasing the first lever arm (distance from crestal bone to abutment) in unsplinted resilient attachments in a mandibular implant overdenture, the stresses generated in bone are decreased. Also, by increasing the second lever arm (distance from occlusal plane to abutment), the stresses in bone were decreased. Finally, this study found that Locator attachments could generate more stresses than ball attachments in the same CHS. Author information Dr. Ebadian is an associate professor, Dental Implant Research Center and Department of Prosthodontics, School of Dentistry, Isfahan University of Medical Sciences, Iran, where Dr. Khodaeian is an assistant professor. Dr. Farzin is a professor, Department of Mechanical Engineering, Isfahan University of Technology, Iran. Mr. Talebi is a doctoral student, Department of Mechanical Engineering, Amirkabir University of Technology, Tehran, Iran. References 1. Feine JS, Carlsson GE, Awad MA, et al. The McGill consensus statement on overdentures. Mandibular two-implant overdentures as first choice standard of care for edentulous patients. Gerodontology. 2002; 19(1):3-4. 2. Fanuscu MI, Caputo AA. Influence of attachment systems on load transfer of an implant-assisted maxillary overdenture. J Prosthodont. 2004;13(4):214-220. 3. Tokuhisa M, Matsushita Y, Koyano K. In vitro study of a mandibular implant overdenture retained with ball, magnet, or bar attachments: comparison of load transfer and denture stability. Int J Prosthodont. 2003;16(2):128-134. 4. Naert I, Alsaadi G, Quirynen M. Prosthetic aspects and patient satisfaction with two-implant-retained mandibular overdentures: a 10-year randomized clinical study. Int J Prosthodont. 2004;17(4):401-410. 5. Naert I, Alsaadi G, van Steenberghe D, Quirynen M. A 10-year randomized clinical trial on the influence of splinted and unsplinted oral implants retaining mandibular overdentures: peri-implant outcome. Int J Oral Maxillofac Implants. 2004;19(5):695-702. 66 January/February 2015 6. Heckmann SM, Winter W, Meyer M, Weber HP, Wichmann MG. Overdenture attachment selection and the loading of implant and denture-bearing area. Part 1: in vivo verification of stereolithographic model. Clin Oral Implants Res. 2001;12(6):617-623. 7. Oetterli M, Kiener P, Mericske-Stern R. A longitudinal study on mandibular implants supporting an overdenture: the influence of retention mechanism and anatomic-prosthetic variables on periimplant parameters. Int J Prosthodont. 2001;14(6):536-542. 8. Gotfredsen K, Holm B. Implant-supported mandibular overdentures retained with ball or bar attachments: a randomized prospective 5-year study. Int J Prosthodont. 2000;13(2):125-130. 9. Cune M, van Kampen F, van der Bilt A, Bosman F. Patient satisfaction and preference with magnet, bar-clip, and ball-socket retained mandibular implant overdentures: a cross-over clinical trial. Int J Prosthodont. 2005;18(2):99-105. 10. Chen IC, Brudvik JS, Mancl LA, Rubenstein JE, Chitswe K, Raigrodski AJ. Freedom of rotation of selected overdenture attachments: an in vitro study. J Prosthet Dent. 2011;106(2):78-86. 11. Cakarer S, Can T, Yaltirik M, Keskin C. Complications associated with the ball, bar and Locator attachments for implant-supported overdentures. Med Oral Patol Oral Cir Bucal. 2011;16(7):e953-e959. 12. Sadowsky SJ, Caputo AA. Effect of anchorage systems and extension base contact on load transfer with mandibular implant-retained overdentures. J Prosthet Dent. 2000;84(3):327-334. 13. Chun HJ, Park DN, Han CH, Heo SJ, Heo MS, Koak JY. Stress distributions in maxillary bone surrounding overdenture implants with different overdenture attachments. J Oral Rehabil. 2005;32(3):193-205. 14. Walton JN, MacEntee MI. Problems with prostheses on implants: a retrospective study. J Prosthet Dent. 1994; 71(3):283-288. 15. Dudic A, Mericske-Stern R. Retention mechanisms and prosthetic complications of implant-supported mandibular overdentures: long-term results. Clin Implant Dent Relat Res. 2002;4(4):212-219. 16. Mericske-Stern R. Three-dimensional force measurements with mandibular overdentures connected to implants by ball-shaped retentive anchors. A clinical study. Int J Oral Maxillofac Implants. 1998;13(1):36-43. 17. Grossmann Y, Finger IM, Block MS. Indications for splinting implant restorations. J Oral Maxillofac Surg. 2005;63(11):1642-1652. 18. Serio FG. Clinical rationale for tooth stabilization and splinting. Dent Clin North Am. 1999;43(1):1-6, v. 19. Chaimattayompol N, Arbree NS. Assessing the space limitation inside a complete denture for implant attachments. J Prosthet Dent. 2003;89(1):82-85. 20. Ahuja S, Cagna DR. Defining available restorative space for implant overdentures. J Prosthet Dent. 2010;104(2):133-136. 21. Misch CE, Goodacre CJ, Finley JM, et al. Consensus conference panel report: crown-height space guidelines for implant dentistry-Part 1. Implant Dent. 2005;14(4):312-318. 22. Barbier L, Schepers E. Adaptive bone remodeling around oral implants under axial and nonaxial loading conditions in the dog mandible. Int J Oral Maxillofac Implants. 1997;12(2):215-223. 23. Nissan J, Ghelfan O, Gross O, Priel I, Gross M, Chaushu G. The effect of crown/implant ratio and crown height space on stress distribution in unsplinted implant General Dentistry www.agd.org supporting restorations. J Oral Maxillofac Surg. 2011; 69(7):1934-1939. 24. Ebadian B, Farzin M, Talebi S, Khodaeian N. Evaluation of stress distribution of implant-retained mandibular overdenture with different vertical restorative spaces: a finite element analysis. Dent Res J (Isfahan). 2012; 9(6):755-761. 25. Nickel JC, McLachlan KR. In vitro measurement of the frictional properties of the temporomandibular joint disc. Arch Oral Biol. 1994;39(4):323-331. 26. Bonnet AS, Postaire M, Lipinski P. Biomechanical study of mandible bone supporting a four-implant retained bridge: finite element analysis of the influence of bone anisotropy and foodstuff position. Med Eng Phys. 2009;31(7):806-815. 27. Greco GD, Jansen WC, Landre Junior J, Seraidarian PI. Stress analysis on the free-end distal extension of an implant-supported mandibular complete denture. Braz Oral Res. 2009;23(2):182-189. 28. Zampelis A, Rangert B, Heijl L. Tilting of splinted implants for improved prosthodontic support: a two-dimensional finite element analysis. J Prosthet Dent. 2007;97(6 Suppl):S35-S43. 29. Menicucci G, Mossolov A, Mozzati M, Lorenzetti M, Preti G. Tooth-implant connection: some biomechanical aspects based on finite element analyses. Clin Oral Implants Res. 2002;13(3):334-341. 30. Maeda Y, Wood WW. Finite element method simulation of bone resorption beneath a complete denture. J Dent Res. 1989;68(9):1370-1373. 31. Porter JA Jr, Petropoulos VC, Brunski JB. Comparison of load distribution for implant overdenture attachments. Int J Oral Maxillofac Implants. 2002;17(5):651-662. 32. Sadowsky SJ. Mandibular implant-retained overdentures: a literature review. J Prosthet Dent. 2001;86(5): 468-473. 33. Karabuda C, Yaltirik M, Bayraktar M. A clinical comparison of prosthetic complications of implant-supported overdentures with different attachment systems. Implant Dent. 2008;17(1):74-81. 34. Naert I, Quirynen M, Hooghe M, van Steenberghe D. A comparative prospective study of splinted and unsplinted Branemark implants in mandibular overdenture therapy: a preliminary report. J Prosthet Dent. 1994;71(5):486-492. 35. Misch CE. Consideration of biomechanical stress in treatment with dental implants. Dent Today. 2006; 25(5):80, 82, 84-85; quiz 85. 36. Watson RM, Jemt T, Chai J, et al. Prosthodontic treatment, patient response, and the need for maintenance of complete implant-supported overdentures: an appraisal of 5 years of prospective study. Int J Prosthodont. 1997;10(4):345-354. 37.van Kampen F, Cune M, van der Bilt A, Bosman F. Retention and postinsertion maintenance of bar-clip, ball and magnet attachments in mandibular implant overdenture treatment: an in vivo comparison after 3 months of function. Clin Oral Implants Res. 2003; 14(6):720-726. 38. Kleis WK, Kammerer PW, Hartmann S, Al-Nawas B, Wagner W. A comparison of three different attachment systems for mandibular two-implant overdentures: one-year report. Clin Implant Dent Relat Res. 2010; 12(3):209-218. 39. Celik G, Uludag B. Photoelastic stress analysis of various retention mechanisms on 3-implant-retained mandibular overdentures. J Prosthet Dent. 2007;97(4): 229-235. 40. Kenney R, Richards MW. Photoelastic stress patterns produced by implant-retained overdentures. J Prosthet Dent. 1998;80(5):559-564. 41. Takeshita S, Kanazawa M, Minakuchi S. Stress analysis of mandibular two-implant overdenture with different attachment systems. Dent Mater J. 2011. Available at: https://www.jstage.jst.go.jp/article/dmj/30/6/30_ 2011-134/_article. Accessed Ocotber 6, 2014. 42. Cehreli MC, Karasoy D, Kokat AM, Akca K, Eckert S. A systematic review of marginal bone loss around implants retaining or supporting overdentures. Int J Oral Maxillofac Implants. 2010;25(2):266-277. 43. Ciftci Y, Canay S. The effect of veneering materials on stress distribution in implant-supported fixed prosthetic restorations. Int J Oral Maxillofac Implants. 2000; 15(4):571-582. 44. Satoh T, Maeda Y, Komiyama Y. Biomechanical rationale for intentionally inclined implants in the posterior mandible using 3D finite element analysis. Int J Oral Maxillofac Implants. 2005;20(4):533-539. 45. Misch C. The edentulous mandible: an organized approach to implant supported overdentures. In: Misch CE, ed.. Contemporary Implant Dentistry. 3rd ed. St. Louis: Mosby; 2007:297-298. 46. Pasciuta M, Grossmann Y, Finger IM. A prosthetic solution to restoring the edentulous mandible with limited interarch space using an implant-tissue-supported overdenture: a clinical report. J Prosthet Dent. 2005; 93(2):116-120. 47. Lee CK, Agar JR. Surgical and prosthetic planning for a two-implant-retained mandibular overdenture: a clinical report. J Prosthet Dent. 2006;95(2):102-105. 48. Wang TM, Leu LJ, Wang J, Lin LD. Effects of prosthesis materials and prosthesis splinting on peri-implant bone stress around implants in poor-quality bone: a numeric analysis. Int J Oral Maxillofac Implants. 2002; 17(2):231-237. 49. Guichet DL, Yoshinobu D, Caputo AA. Effect of splinting and interproximal contact tightness on load transfer by implant restorations. J Prosthet Dent. 2002; 87(5):528-535. 50. Schulte J, Flores AM, Weed M. Crown-to-implant ratios of single tooth implant-supported restorations. J Prosthet Dent. 2007;98(1):1-5. 51. Nissan J, Gross O, Ghelfan O, Priel I, Gross M, Chaushu G. The effect of splinting implant-supported restorations on stress distribution of different crown-implant ratios and crown height spaces. J Oral Maxillofac Surg. 2011;69(12):2990-2994. 52. Misch CE, Steignga J, Barboza E, Misch-Dietsh F, Cianciola LJ, Kazor C. Short dental implants in posterior partial edentulism: a multicenter retrospective 6-year case series study. J Periodontol. 2006;77(8):1340-1347. 53. Natali AN, Pavan PG, Ruggero AL. Evaluation of stress induced in peri-implant bone tissue by misfit in multiimplant prosthesis. Dent Mater. 2006;22(4):388-395. 54. Bellini CM, Romeo D, Galbusera F, et al. Comparison of tilted versus nontilted implant-supported prosthetic designs for the restoration of the edentuous mandible: a biomechanical study. Int J Oral Maxillofac Implants. 2009;24(3):511-517. 55. Silva GC, Mendonca JA, Lopes LR, Landre J Jr. Stress patterns on implants in prostheses supported by four or six implants: a three-dimensional finite element analysis. Int J Oral Maxillofac Implants. 2010;25(2): 239-246. Manufacturers Abaqus, Inc., Pawtucket, RI 415.496.9436, www.abaqus.net BioHorizons IPH, Inc., Birmingham, AL 888.246.8338, www.biohorizons.com Dassault Systemes Americas Corp., Waltham, MA 781.810.3000, www.3ds.com DENTSPLY International, York, PA 800.877.0020, www.dentsply.com GOM mbH, Braunschweig, Germany 49.531.390290, www.gom.com Heraeus Kulzer, South Bend, IN 800.435.1785, www.heraeus-dental-us.com www.agd.org There is an article on PROSTHODONTICS/REMOVABLE in the online edition. •Management of severe mandibular deviation following partial mandibular resection: a case report Visit www.agd.org/GeneralDentistry AGDPODCAST Controversies in Implant Dentistry General Dentistry January/February 2015 67 Exercise No. 363 Fixed Removable Hybrid Prosthesis Subject Code 674 The 15 questions for this exercise are based on the article, Stress analysis of mandibular implant-retained overdenture with independent attachment system: effect of restoration space and attachment height, on pages 61-67. This exercise was developed by Robert A. Busto, DMD, MBA, FAGD, in association with the General Dentistry Self-Instruction committee. 1. All of the following are factors for selecting the optimal mandibular overdenture attachment except one. Which is the exception? A. required retention B. patient finances C. patient compliance D. jaw morphology 2. The ball attachment places_______ stress on implants and produces ______ bending movement than the bar-clip attachment. A. less; less B. more; less C. less; more D. more; more 3. What is the minimum vertical restorative space (mm) required for using Locator attachments on an implant-supported overdenture? A. 12.5 B. 10.5 C. 8.5 D. 6.5 4. The crown height space is the distance from the ______ to the ______ in implant-supported prostheses. A. mandibular crest of alveolar bone; maxillary crest of alveolar bone B. most superior point of the implant attachment; plane of occlusion C. crest of the alveolar bone; most superior point of the implant attachment D. crest of the alveolar bone; plane of occlusion 5. Increasing the crown height space by 1 mm results in a _____% increase in the cervical load on a fixed implant prosthesis. A. 10 B. 15 C.20 D. 25 Reading the article and successfully completing the exercise will enable you to understand the: •theoretical force distribution on implants and surrounding bone; •differences between ball and Locator attachments; and •unfavorable biomechanical scenarios for implant overdenture treatment. 6. If the vertical restorative space is 12 mm, which implant-supported overdenture attachment(s) is/are acceptable? A. Locators only B. Locators and balls C. Locators and bar clips D. Locators, balls, and bar clips 7. How were the implants in this study placed in relation to the occlusal plane? A. Angled 30 degrees B. Angled 45 degrees C. Angled 75 degrees D. Angled 90 degrees 8. The implants in this study were placed with an interimplant distance of ___ mm. A. 14 B. 16 C. 18 D. 20 9. Which combination of implant collar height and occlusal plane height (mm) resulted in maximum stress? A. 1; 9 B. 1; 15 C. 2; 9 D. 2; 15 10. Cakarer et al reported that the Locator attachments receive greater stress than ball attachments. Celik & Uludag reported that Locator attachments have a higher implant failure rate. A. Both statements are true. B. The first statement is true; the second is false. C. The first statement is false; the second is true. D. Both statements are false. 11. The Locator implant is ______ retentive and ______ resilient than the ball attachment. A. equally; less B. more; equally C. more; less D. less; more 12. The level of stress correlated to bone resorption has not been clearly defined in the literature. Finite element analysis studies can produce clinical conclusions to determine how much stress an implant can take before bone resorption. A. Both statements are true. B. The first statement is true; the second is false. C. The first statement is false; the second is true. D. Both statements are false. 13. In a restricted vertical space, this study recommends using a _____ attachment system with minimum collars to address stress concerns. A. Locator B. ball C. Dalbo D. bar clip 14. Increasing the crown height space in removable implant overdentures decreases the stress generated in the bone. Increasing the crown height space in fixed implant prostheses increases the stress in the bone. A. Both statements are true. B. The first statement is true; the second is false. C. The first statement is false; the second is true. D. Both statements are false. 15. In unsplinted implants, decreasing the distance from the crest of the bone to the __________ will decrease the stresses generated in the bone. A. abutment B. plane of occlusion C. apex of the implant D. facial midline Answer form is on the inside back cover. Answers for this exercise must be received by December 31, 2015. 68 January/February 2015 General Dentistry www.agd.org Oral Medicine, Oral Diagnosis, Oral Pathology p53 expression in oral lichenoid lesions and oral lichen planus A. Arreaza, MSc n H. Rivera, MSc n M. Correnti, PhD The aim of this article was to compare the expression of p53 protein in oral lichen planus (OLP) and oral lichenoid reaction (OLR). The study population consisted of 65 patients—31 diagnosed with OLP and 34 with OLR. The results showed more p53 positive cases in the OLP group than in the OLR group. However, the difference between the 2 groups was not statistically significant (P = 0.114). The most common immunolocalization O ral lichen planus (OLP) is a chronic inflammatory condition that involves the skin and oral mucosa.1,2 It mainly affects women between 30 and 50 years of age, and it is not common in children.1 The prevalence of this condition represents 1%-4% of the global population with no apparent ethnic predisposition.1 OLP has a variety of clinical manifestations: papuloreticular, linear, plaque, erosive or ulcerative, and macular or pigmented. Reticular or plaque forms frequently occur with single, asymptomatic lesions being the only manifestation of the disease. However, erythematous or ulcerative clinical presentations may also occur.1-4 OLP is caused by an immune T cell response to an unidentified antigen in the skin or oral mucosa of patients who have a genetic predisposition to the disease. The initial response is an increased production of cytokines produced by TH1 lymphocytes with gene polymorphism in molecules such as IFN-γ and TNF-α in oral and skin lesions. Another indicator of OLP pathogenesis is the presence of dendritic cells (stromal plasmacytoids and Langerhans), triggered by chemotactic agonists expressed in the vascular endothelium.1-3 The INF-γ/TNF-α cytokine production induces cytotoxicity against keratinocytes, by activating natural killer cells and cytotoxic T lymphocytes, eventually resulting in apoptosis via the Fas ligand pathway. This is caused by adhesion molecules— such as VCAM and ICAM-1—which enable the activated T cells to migrate to the oral epithelia or skin. The T cell was observed at the basal cell layer. Due to the chance of potential future malignancy, follow-up for all cases is recommended. Received: May 22, 2013 Revised: September 7, 2013 Accepted: October 2, 2013 Key words: p53, oral lichen planus, lichenoid lesions migration to these sites leads to the expression of other molecules at the basal cell layer, resulting in lymphocyte linkage to the epithelium. This linkage triggers an intense production of IFN-γ and TNF-α, leading to matrix metalloproteinases and p53 overexpression, ending in apoptosis.1-3 but the putative mechanism remains unknown1,2,4,7-10 Some studies have shown that OLR lesions may have an increased risk of malignant transformation.1,4,6 The annual rate of OLP malignant transformation has been estimated to be 0.2%1% worldwide.1,4 Oral lichenoid reaction p53 expression Oral lichenoid reaction (OLR) presents as lesions that are clinically and histologically identical to OLP, but with an identifiable etiologic factor.1,5,6 They may be classified as oral lichenoid lesions as a result of contact with dental materials— particularly amalgam—due to both an adverse reaction to medications or graftversus-host disease (GVHD).1-3 Clinically, OLR may be observed as erosive lesions that occur unilaterally. Histologically, OLR presents similarly to OLP, with a larger proportion of diffuse lymphocytic infiltrate, plasma cells, and citoid bodies.1-3,5,6 Both OLP and OLR may exhibit a band-like lymphocytic infiltrate that is not patognomonic, which is similar to other autoimmune diseases such as lupus erythematous.1,5,6 The 2 conditions differ mainly in their outcome and the treatment modality: OLP lesions become chronic, while OLR lesions tend to disappear as soon as the etiologic cause is eliminated.1,5,6 The malignant potential of OLP remains controversial. Some retrospective studies and case reports have documented OLP transforming into oral squamous cell carcinoma (SCC), and there are other studies on OLR malignant transformation related to GVHD, www.agd.org p53 is an oncoprotein involved in the suppression of the proliferation of DNAdamaged cells via cell cycle regulation that results in the apoptosis of these cells.11 Impaired function of the p53 gene has been implicated in the development and progression of oral epithelial dysplasia and oral SCC.11,12 Therefore, detection of p53 changes may help in the identification of high risk lesions or potentially malignant OLP cases.12 Due to its established role as a genomic “guardian,” the wild p53 protein has been connected to a low potential for malignant transformation in OLP cells.13 In addition, it has been recently shown that the human TP53 gene encodes at least 9 different isoforms; while the function of these novel isoforms is still not clearly understood, they have been amplified (via a quantitative real-time polymerase reaction) in samples of SCC in the head and neck.14 This could indicate a tumorrelated role for these isoforms. Evaluating the oncogenic potential by using different markers could help researchers to analyze the ethiopathogenesis and potentially serve as a carcinogenic prognosticator for these conditions. This study sought to compare the expression of p53 protein in OLP and OLR. General Dentistry January/February 2015 69 Oral Medicine, Oral Diagnosis, Oral Pathology p53 expression in oral lichenoid lesions and oral lichen planus Table 1. Anatomical locations of oral lichen planus (OLP) and oral lichenoid reaction (OLR) in this study. Table 2. Incidence of histological features found in the OLP and OLR groups. Anatomical location Histological feature OLP (n = 31) OLP (n = 31) OLR (n = 34) Buccal mucosa (bilateral occurrence) 14 0 Inflammatory band-like infiltrate 31 34 Buccal mucosa (unilateral occurrence) 1 9 Acanthosis 19 21 Internal lip 3 6 Basal cell degeneration 17 14 Maxillary alveolar ridge mucosa 1 5 Parakeratosis 3 15 Hard palate 3 3 Cytoid bodies 10 6 Dorsum of tongue 3 1 Orthokeratosis 9 5 Attached gingiva 2 2 Ulceration 4 7 Buccal vestibule mucosa 1 5 Epithelial atrophy 3 3 Others (retromolar area, soft palate, floor of the mouth, ventral tongue, mandibular ridge mucosa) 3 3 Others (amalgam remnants, basal cell shedding, sialadenitis, vasculitis, glandular fibrosis, ductal ectasia) 4 7 Materials and methods The study population consisted of 65 biopsy cases—31 diagnosed with OLP and 34 with OLR at the Oral Pathology Laboratory, Faculty of Dentistry, Central University of Venezuela. These cases were analyzed and histologically classified according to Van der Meij et al.10 Paraffin embedded sections (3 μm) were deparaffinized and subjected to an antigen retrieval solution (pH = 6) (Dako North America, Inc.) for 1 hour. Endogenous peroxidase was blocked by immersing the sections in methanol and 3% hydrogen peroxide for 30 minutes. Next, a primary antibody p53 clone in a 1:50 dilution (DO7, Dako North America, Inc.) was applied to the sections for 30 minutes. A detection system (EnVision, Dako North America, Inc.) was utilized using diaminobenzidine for 10 minutes. Positive and negative controls were performed. The slides were observed under light microscopy. Expression of the proteins was studied by cell count in 4 high magnification fields (40X). The immunoreactivity in each section was graded according to the number of positively stained nuclei in a field and grouped in order from the least (-) to most (+++) positive reaction: <1% nuclei (-), up to 30% nuclei (+), 30%-70% nuclei (++), and >70% (+++). Separate counts were made in the basal layer, suprabasal layers, and inflammatory infiltrate. Counts 70 OLR (n = 34) January/February 2015 were made of the total cells and of the marked cells in each field, and the mean percentages of expression were calculated for each case. Brown-stained cells were considered positive, regardless of the intensity of staining. Immunoreaction intensity was recorded as mild, moderate, or strong. The Ethics Committee of the Faculty of Dentistry, Central University of Venezuela, approved the study. All patients signed a written informed consent form. Statistical analysis The p53 immunoreactivity was correlated in the OLP and OLR groups, while variables—including gender, age group, and anatomical site—were analyzed separately. A Fisher exact test was performed to assess the correlation between variables. The level of significance was determined to be P < 0.05. The statistical analysis was performed using SPSS statistical software (version 16.0; SPSS, Inc.). Results The distribution of OLP and OLR according to age was 59.5 (±11.7) years and 57.0 (±15.1) years in the OLP and OLR groups, respectively. Gender distribution in the OLP group was 84.6% female and 19.3% male; the distribution in the OLR group was 79.4% female and 20.6% male. The buccal mucosa was the most common anatomical site in both groups. With 1 exception, the buccal General Dentistry www.agd.org Table 3. Histological location of p53 expression in the OLP and OLR groups. OLP (n = 31) OLR (n = 34) 13 11 Basal cell/infiltrate 9 2 Inflammatory infiltrate 0 3 Basal/suprabasal 1 2 Suprabasal/basal/ infiltrate 1 0 Submucosa 0 1 Histological location Basal cell layer mucosa occurrence was bilateral in the OLP group and unilateral in the OLR group (Table 1). According to histological analysis, all cases of OLP and OLR showed similar findings of an inflammatory band-like infiltrate and acanthosis. Basal cell liquefaction was evidenced in both groups. Citoid bodies were present in 32.2% of the OLP cases, while parakeratosis was present in 44.1% of the OLR cases (Table 2). In terms of immunohistochemical analysis, p53 expression was observed in 77.4% of the OLP cases and 55.9% of the OLR cases. However, the difference between the 2 groups was not statistically significant (P = 0.114). Fig. 1. A sample of oral lichen planus (OLP) with p53 expression at the basal cell layer and an inflammatory infiltrate (immunostain, magnification 20X). Fig. 2. A sample of oral lichenoid reaction (OLR) with p53 expression at the basal cell layer and inflammatory infiltrate (immunostain, magnification 20X). Fig. 3. A sample of OLP with nuclear immunolocalization of p53 at the basal cell layer (immunostain, magnification 40X). Fig. 4. A sample of OLR with nuclear immunolocalization of p53 at the basal cell layer and inflammatory infiltrate (immunostain, magnification 40X). For both groups, nuclear p53 immunolocalization was most common at the basal cell layer. Basal cell/infiltrate locations were seen in 29.0% and 5.9% in the OLP and OLR groups, respectively (Table 3). It is noteworthy that p53 positivity was found both alone and in combination with other histological localizations (Fig. 1 and 2). Immunostaining at 40X magnification revealed that p53 was similarly expressed in both groups. The results showed that 38.7% and 26.5% were graded (+) in the OLP and OLR groups, respectively; 25.8% and 20.6% were graded (++) in the OLP and OLR groups, respectively; 12.9% and 8.8% were graded (+++) in the OLP and OLR cases, respectively. These positively stained nuclei were located mainly in the basal cell layer (Fig. 3 and 4). The intensity of the stain was mild to moderate in the majority of cases: mild staining was found in 25.8% and 20.6% of the OLP and OLR groups, respectively; moderate staining was found in 29.0% and 20.5% of the OLP and OLR groups, respectively. There was strong intensity staining in 22.6% and 14.7% of the OLP and OLR cases, respectively. Discussion Regarding the age group and gender distribution in the present study, women were more affected in the fifth decade. These www.agd.org data were consistent with the OLP and OLR epidemiology previously documented in the literature.1 In terms of anatomical location, the buccal mucosa was the most common site in both groups, in agreement with the literature.1-4 Bilateral occurrence was a common feature among the OLP cases in this study, as it is in the literature.1 White striations were observed in both groups. The appearance of these asymptomatic striations are considered to be a good clinical prognostic for malignant transformation.1-5 Lesions symptomatic of erosion/ulcers were more regularly observed in the OLR goup in comparison to the OLP group; the OLP cases presented nonpainful white plaque General Dentistry January/February 2015 71 Oral Medicine, Oral Diagnosis, Oral Pathology p53 expression in oral lichenoid lesions and oral lichen planus as a primary clinical sign. Based on similar studies, the presence of the erosive lesions in the OLR group indicate a potential for malignant transformation.1,4 p53 positivity was observed in the majority of the lesions in both groups. While the OLP group had a higher percentage of p53 positivity, the difference between the 2 groups was deemed not to be statistically significant. The data in this study suggests an antiapoptotic potential at the basal cell layer. Under normal conditions, the epithelia does not show apoptotic basal cells, but in OLP and OLR, the lymphocytic stimulation should lead to an apoptotic state in these cells that produces an apoptotic response as evidenced by the presence of Civatte bodies (cytoid bodies) and the hydropic degeneration of the epithelial cells layer. The maintenance of a chronic inflammatory response at this level can result in cellular genome mutations that lead to an alteration of this apoptotic response. One of these mutations may be evidenced by the expression of altered p53 in the basal layer of the epithelium in both diseases. This mutation can alter the balance between the rate of epithelial cell replication and apoptosis, resulting in the emergence of malignancies.11 Despite the small sample size in this study, the results—in consideration of the widely accepted belief that the presence of white striations is a good prognostic for malignant transformation—indicate the need for clinicians to follow-up on any incidence of white striations in OLP patients, and consider a new biopsy when any clinical changes appear or when erosive symptomatic cases do not respond to therapy.1-5 Parakeratosis was a common histologic characteristic in the OLR group (44%) compared to the OLP group (9.6%), suggesting that an inflammatory response generates the production of a wide layer of parakeratin within the corneal stratum, leading to apoptosis while maintaining the nuclei. Several studies have mentioned the potential of OLP to transform into SCC.4,8,9,12 The etiology of this process remains unknown, however protein alterations related to apoptosis seem to be involved.14 Other etiologic factors including viral infections and loss of heterozigocity have also been mentioned.15-17 72 January/February 2015 The role of p53 as a prognostic marker for SCC, as well as other malignant disorders, has been widely documented.17 Sadafi et al reported a higher incidence of p53 and p21 in OLP patients, suggesting a need for follow-up inspection on these cases.18 Although previous studies have indicated that OLR is more likely to become malignant than OLP, the follow-up of OLP patients should not be dismissed readily, since these cases may also present an oncogenic potential.18,19 The anti-p53 antibody, pAb240, recognizes an evolutive preserved epitope that is present on the p53 protein. This antibody uses inmmunoblots with denaturated extracts from human and animal models. Gonzalez-Moles et al found fewer positive OLP cases with pAb240 compared to the p53 DO7 clone.13 Future studies may be necessary to verify these results. Conclusion In this study, the OLP group showed more positive p53 cases compared to the OLR group. Dentists should follow-up all OLP and OLR cases, due to the possibility of malignant transformation. Author information Dr. Arreaza is an aggregate professor, Pharmacology Department, Faculty of Dentistry, Central University of Venezuela, Caracas, where Drs. Rivera and Correnti are professors. Disclaimer The authors have no financial, economic, commercial, and/or professional interests related to topics presented in this article. References 1. Carrozzo M, Thorpe R. Oral lichen planus: a review. Minerva Stomatol. 2009;58(10):519-537. 2. Farhi D, Dupin N. Pathophysiology, etiologic factors, and clinical management of oral lichen planus, part I: facts and controversies. Clin Dermatol. 2010;28(1): 100-108. 3. Scully C, Carrozzo M. Oral mucosal disease: lichen planus. Br J Oral Maxillofac Surg. 2008;46(1);15-21. 4. Bombeccari GP, Guzzi G, Tettamanti M, et al. Oral lichen planus and malignant transformation: a longitudinal cohort study. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2011;112(3):328-334. 5. Rad M, Hashemipoor MA, Mojtahedi A, et al. Correlation between clinical and histopathologic diagnoses of oral lichen planus based on modified WHO diagnostic criteria. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2009;107(6):796-800. General Dentistry www.agd.org 6. Cortes-Ramirez DA, Rodríguez-Tojo MJ, Gainza-Cirauqui ML, Martinez-Conde R, Aguirre-Urizar JM. Overexpression of cyclooxygenase-2 as a biomarker in different subtypes of the oral lichenoid disease. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2010; 110(6):738-743. 7. Accurso BT, Warner BM, Knobloch TJ, et al. Allelic imbalance in oral lichen planus and assessment of its classification as a premalignant condition. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2011;112(3): 359-366. 8. Kumagai K, Horikawa T, Gotoh A, et al. Up-regulation of EGF receptor and its ligands, AREG, EREG, and HBEGF in oral lichen planus. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2010;110(6):748-754. 9. Ramos-e-Silva M, Jacques CD, Carneiro SD. Premalignant nature of oral and vulval lichen planus: facts and controversies. Clin Dermatol. 2010;28(5):563-567. 10. Van der Meij E, Schepman K, Van der Waal I. The possible premalignant character of oral lichen planus and oral lichenoid lesions: a prospective study. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2003;96(2): 164-171. 11.Agha-Hosseini F, Mirzaii-Dizgah I. p53 as a neoplastic biomarker in patients with erosive and plaque like forms of oral lichen planus. J Contemp Dent Pract. 2013;14(1):1-3. 12. Ebrahimi M, Nylander K, Van der Waal I. Oral lichen planus and the p53 family: what do we know? J Oral Pathol Med. 2011;40(4):281-285. 13. Gonzales-Moles MA, Gil-Montoya JA, Ruiz-Avila I, Esteban F, Bascones-Martinez A. Differences in the expression of p53 protein in oral lichen planus based on the use of monoclonal antibodies DO7 and pAb 240. Oral Oncol. 2008;44(5):496-503. 14. Ebrahimi M, Boldrup L, Coates PJ, Wahlin YB, Bourdon JC, Nylander K. Expression of novel p53 isoforms in oral lichen planus. Oral Oncol. 2008;44(2):156161. 15. Gorsky M, Epstein JB. Oral lichen planus: malignant transformation and human papilloma virus: a review of potential clinical implications. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2011;111(4):461-464. 16. Arreaza A, Correnti M, Avila M. Deteccion del virus Epstein-Barr en lesiones de liquen plano bucal. Acta Odontol Vzla. 2010;48(3):1-9. 17.Georgakopoulou EA, Troupis TG, Troupis G, Gorgoulis VG. Update of the cancer-associated molecular mechanisms in oral lichen planus, a disease with possible premalignant nature. J BUON. 2011;16(4):613616. 18. Sadafi RA, Al Jaber SZ, Hammad HM, Hamasha AA. Oral lichen planus shows higher expressions of tumor suppressor gene products of p53 and p21 compared to oral mucositis. An immunohistochemical study. Arch Oral Biol. 2010;55(6):454-461. 19. Cortes D, Agurne-Urribarri M, Gainza ML, Echevarria MA, Aguirre JM. Enfermedad liquenoide oral: condicion premaligna emergente y controvertida. Gac Med Bilbao. 2010;107(2):72-78. Manufacturers Dako North America, Inc., Carpinteria, CA 805.566.6655, www.dako.com SPSS, Inc., Quarry Bay, Hong Kong 852.2811.9662, www.spss.com Dental Materials Effect of imaging powders on the bond strength of resin cement Christopher R. Jordan, DMD, MS n Clifton W. Bailey, DDS n Deborah L. Ashcraft-Olmscheid, DMD, MS n Kraig S. Vandewalle, DDS, MS The application and incomplete removal of a computer-aided design/ computer-aided manufacture imaging powder may affect the dentin surface prior to bonding a ceramic restoration. The purpose of this study was to compare the effect of imaging powder residue on the shear bond strength of a self-adhesive resin cement to dentin. Mounted human third molars were sectioned coronally with a diamond saw to expose the dentin, which was then prepared with a diamond bur mounted in a custom jig. The dentin surface was sprayed with 3 different imaging powders. The 3 powder groups were then divided into 3 subgroups based on the method of powder removal: no rinse, 1-second rinse, and 10-second rinse. A control group was created that had no application of imaging powder. T he notion of computer-aided design/ computer-aided manufacture (CAD/ CAM) dentistry was first introduced in the late 1970s by Duret.1 In 1987, Sirona Dental Systems, Inc. released the first version of a chairside economical restoration of esthetic ceramics (CEREC) technology.2 Since then, this all-ceramic restoration treatment has been simplified and improved, and numerous systems have been developed and marketed.2 The most advantageous aspect of this technology is the capability to create and mill a restoration in the dental office, thus reducing costs and streamlining treatment. As of 2009, there were approximately 25,000 CEREC users worldwide.2,3 CAD/CAM is also being used to restore endodontically treated teeth with endocrowns and in conjunction with cone beam volumetric tomography to plan and restore dental implants.4,5 Very little research, however, has been done to support specific methods and standard processes for the restorative dentist. Additionally, manufacturers produce a variety of materials that can be used at different steps. The practitioner is tasked with selecting the imaging powder and cement that have the best performance properties. The majority of the research to date has been focused on the properties of the restoration itself, as well as the marginal adaptation, retention, or durability of a particular cement.6-26 A review of these clinical studies found that the A self-adhesive resin cement was bonded to the surfaces and loaded to failure in a universal testing machine after 24 hours of storage. Data was analyzed with Kruskal-Wallis and Mann-Whitney nonparametric tests. The bonding to dentin surfaces of the powder groups that were rinsed for 1 or 10 seconds were not significantly different from each other or the nonpowdered control. The type of imaging powder did not significantly affect the bond strength. The nonrinsed powdered dentin surface had a significant reduction in bond strength compared to both the control and the rinsed powdered surfaces. Received: April 18, 2013 Accepted: July 17, 2013 longevity of posterior dental restorations was dependent upon many factors related to the chosen materials, the patient, and the dentist. According to a 2001 study, annual failure rates in posterior stressbearing restorations were: 0% to 7.0% for amalgam restorations, 0% to 9.0% for direct composites, 1.4% to 14.4% for glass ionomers and derivatives, 0% to 11.8% for composite inlays, 0% to 7.5% for ceramic restorations, 0% to 4.4% for CAD/CAM ceramic restorations, and 0% to 5.9% for cast gold inlays and onlays.20 The principle reasons for failure were secondary caries, fracture, marginal deficiencies, wear, and postoperative sensitivity.20 The type of luting agent is considered to be one of the key factors in determining a restoration’s longevity.26,27 A critical step in any indirect restoration is the capture of the preparation in an impression. When using a CAD/CAM system to mill a restoration, the impression is made by using a camera to digitally scan the tooth (or a cast), then using a computer program to virtually design the restoration. The CEREC 3D AC (Sirona Dental Systems, Inc.) system uses a camera that projects blue wavelength light over the area to capture all of the dimensions of the preparation and surrounding teeth and tissues. The blue wavelength light reportedly provides a higher resolution image than the infrared camera used in earlier systems, such as the CEREC 3D AU (Sirona Dental Systems, Inc.).28 www.agd.org In order for the CEREC camera to capture an accurate image, the surface or object to be scanned must be as uniform as possible in its reflectivity. To accomplish this, a titanium dioxide powder is typically used to coat the area. The E4D (Planmeca E4D Technologies) is a chairside imaging and milling system that creates a digital impression from an intraoral scan without the use of reflective powder. The new CEREC Omnicam (Sirona Dental Systems, Inc.) also functions without application of imaging powder. Other systems, such as iTero (Align Technology, Inc.) and Lava C.O.S. (3M ESPE), are used exclusively for digital impressions. Whereas the iTero system does not require powder, the Lava C.O.S. requires a light dusting. The improper use of imaging powder is a possible source of error when fabricating a CEREC 3D restoration.29 The coating can be sprayed on with a delivery unit such as PowderPro (Advanced Dental Instruments LLC), painted on using a liquid such as Scan Film (Dentaco As), or sprayed on with a self-contained propellant and powder system such as Optispray (Sirona Dental Systems, Inc.).30 Cameras record an over-powdered surface as uneven, whereas one with too little powder does not adequately reflect light. The CEREC 3D camera must be positioned appropriately as well. If the camera is not properly oriented in the path of insertion to allow capturing all General Dentistry January/February 2015 73 Dental Materials Effect of imaging powders on the bond strength of resin cement margins, without undercuts, the scan will not capture the necessary data to accurately allow the restoration to be properly designed. As an alternative to intraoral scanning, the practitioner can make a conventional impression and scan the impression, thereby designing the prosthesis from an image captured indirectly. A cast may be fabricated using a scannable stone material—that is made specifically for indirect optical imaging—such as Diamond Die (Hi-Tec Dental Products)—which allows the clinician to eliminate the intraoral use of a powder spray and scanning. However, the impression and cast fabrication requires an additional step, which adds time to the procedure but may result in a more precise scan. A study by da Costa et al compared the marginal gap created with a direct intraoral scan with that of an indirect scan of a model and found no significant difference.31 Another study, however, found that extraoral optical scanning methods provided the highest precision.32 When using powder, Sirona Dental Systems, Inc. recommends their product, CEREC Optispray, but there are powders on the market that contain a reflective compound other than titanium dioxide. Possible alternatives include an economical magnesium stearate spray (Occlude, Pascal International, Inc.) marketed specifically as an aid for seating castings.33 However, no research has been published evaluating the use of Occlude as an alternative intraoral imaging powder for use with a CEREC 3D system. The application and incomplete removal of an imaging powder may affect the bonding of the restoration to the dentin surface. CEREC manufacturers instruct the dentist to clean the surface with air/ water spray, but do not provide detailed directions. There is no current literature that shows whether an air/water rinse adequately removes the powder residue and whether any remaining residue will affect the cement bond. Some systems, such as VITA CEREC Powder (Vident), rely on the application of glycerin to coat the surface prior to applying the powder.34 Most other self-contained systems, such as CEREC Optispray, do not require the separate application of a coating.35 The intent of this study was to provide guidance 74 January/February 2015 for the use of imaging powder and resin cements with a milled all-ceramic restoration using CEREC 3D. RelyX Unicem (3M ESPE) is a dualcuring, self-adhesive resin luting cement for adhesive cementation of indirect composite, metal, or ceramic restorations.36 Self-adhesive resin cements do not require a separate adhesive or etchant, which can be considered a major benefit due to their simplicity of application compared to more traditional resin cements. Relatively little information exists about the composition and adhesive mechanism of these materials. The current selfadhesive cements are 2-part materials that require hand mixing, capsule trituration, or auto-mixing with a dispenser.37 Bond strengths vary among self-adhesive resin cements. Etch-and-rinse cements generally provide the greatest retention.37,38 Selfetching cements provide an intermediate level, while self-adhesive cements are the least retentive.37 The vast majority of the published literature describes one cement, Rely-X Unicem, which was the first commercially available self-adhesive resin cement.36,38 Rely-X Unicem has 2 components: a powder composed of glass, silica, calcium hydroxide, pyrimidine, peroxy compound, and initiator; and a liquid composed of methacrylated phosphoric ester, dimethacrylate, acetate, stabilizer, and initiator.36,38 Studies have suggested that Unicem shows nearly equivalent results to other resin cements in terms of marginal sealing and adaptation.38 However, a separate phosphoric-acid etch of enamel margins has been shown to improve bond strength.39 A review of studies evaluating the physical properties of self-adhesive resin cements suggest that these materials may be expected to show similar clinical performance as other dental cements, but clinical studies are lacking, so long-term conclusions are not possible.38 Self-adhesive resin cements have a significant reduction in dentin bond strength when the dentin is etched with phosphoric acid and a bonding agent is applied.37 The effect of imaging powder and its effective removal on the bond strength of resin cement to dentin is unknown. The purpose of this study was to compare the effects of imaging powder residue on the shear bond strength of a self-adhesive resin cement to dentin. The null hypotheses General Dentistry www.agd.org to be tested were that there would be no significant differences in the bond strength of the self-adhesive resin cement to dentin based on the amount of rinsing, or the type of imaging powder. Materials and methods Extracted human third molars stored in 0.5% chloramine-T were used within 6 months following extraction. The teeth were mounted in dental stone in plastic pipe with the crown exposed and accessible. A diamond saw (Isomet, Buehler) was used to remove ≥2 mm coronal tooth structure to ensure dentin exposure and the proper orientation of the surface relative to the direction of shear force applied. Each specimen was examined under a stereomicroscope (SMZ-1B, Nikon USA) at 10X magnification to ensure complete exposure of the dentin surface with no residual enamel. To simulate a prepared surface, the flat dentin was roughened with a fine diamond bur (No. 837, Brasseler USA) under water spray with a jig that was used to support the height of the handpiece head with the surface of the tooth specimen. The mounted specimens were then divided into 4 groups: 3 powder groups— VITA CEREC Powder, CEREC Optispray, and Occlude—and 1 group that was not powdered and served as a control. Manufacturers’ directions were followed in the application of the powder. For the CEREC Powder application, the glycerin coating was first placed with a brush and gently air-thinned. Next, the VITA CEREC Powder was applied using a PowderPro system (Advanced Dental Instruments LLC). The PowderPro system was attached to the handpiece hose of a dental delivery unit and the VITA CEREC Powder was delivered through a nozzle on the handpiece with the use of a foot pedal. CEREC Optispray and Occlude are self-contained canister systems, and therefore did not require an adhesive-type first coating or use of the PowderPro system.33,35 All powders were applied according to the manufacturers’ instructions with the applicator tip at a standardized distance of 1 inch. The 3 powder groups were then divided into 3 subgroups (n = 10) based on the method of powder removal: no rinse, 1-second rinse, and 10-second rinse. The teeth were rinsed with distilled water Chart 1. Shear bond strength (MPa) and standard deviation (SD) of selfadhesive resin cement (RelyX Unicem) to dentin after treatment with 3 imaging powders (VITA CEREC Powder, CEREC Optispray, and Occlude) and subsequent rinse of different durations (no rinse, 1 second, and 10 seconds). 14 No rinse 1 second 10 seconds Shear bond strength (MPa) 12 10 8 6 4 2 0 VITA CEREC Powder CEREC Optispray Occlude Control Chart 2. Percent fracture mode by powder and rinse groups. Results VITA CEREC Powder no rinse VITA CEREC Powder 1 sec VITA CEREC Powder 10 sec CEREC Optispray no rinse CEREC Optispray 1 sec CEREC Optispray 10 sec Occlude no rinse Occlude 1 sec Occlude 10 sec No powder 0 20 40 60 80100 % Adhesive Cohesive cement using a 3-way syringe tip at a standardized distance of 1 inch. A custom-made vinyl polysiloxane jig was used to maintain the distance and angle. The tooth specimens were then placed in an Ultradent Jig and secured beneath the white nonstick Delrin insert (Ultradent Products, Inc.).The dual-curing resin cement was mixed and applied into the mold according to the manufacturer’s instructions to a height of 4 mm. The cement was cured as recommended by the manufacturer using a Bluephase 16i light-curing unit (Ivoclar Vivadent, Inc.). Mixed Cohesive dentin Irradiance of the curing light was monitored with a radiometer (LED Radiometer, Kerr Corporation) to verify irradiance levels above 1200 mW/cm2. The bonding area was limited to a 2.4 mm diameter circle determined by the Delrin insert. Following the application of the resin cement, all specimens were stored for 24 hours in distilled water at 37°C. The specimens were then loaded perpendicularly at the interface with a customized probe (Ultradent Products, Inc.) in a universal testing machine (Instron Corp.) and tested with a crosshead speed of 1 mm/min until bonding failure occurred. www.agd.org Shear bond strength values (MPa) were calculated from the peak load of failure (Newtons) divided by the specimen surface area.The mean and standard deviation were determined for each group. Data were analyzed with Kruskal-Wallis and MannWhitney statistical tests. Nonparametric data analysis was used since an exploratory graphical analysis found a non-normal distribution of the data. A Bonferroni correction was applied because multiple comparison tests were performed (α = 0.008). Following shear bond strength testing, each specimen was examined using a stereomicroscope (magnification 10X) to determine failure mode as either: adhesive fracture at the cement/adhesive/dentin interface, cohesive fracture in cement, mixed (combined adhesive and cohesive fracture) in either the cement-bond interface or the dentin-bond interface, or cohesive fracture in dentin. The nonrinsed powdered dentin surface had a significant reduction in bond strength compared to the control (nonpowdered) or the rinsed powdered surfaces (P < 0.008). The dentin surfaces that were rinsed for 1 or 10 seconds were not significantly different from the control or from each other. There was no significant difference in the bond strength of resin cement to dentin based on the type of powder (P > 0.086) (Chart 1). The nonrinsed groups failed primarily with adhesive fractures while the rinsed groups failed primarily with adhesive and mixed fractures (Chart 2). Discussion The manufacturer’s instructions for CEREC Optispray advise the user that “as soon as the optical impression has been taken, the surface should be cleaned with air/water spray.”35 But no published articles could be found that had studied the amount of rinse time required to remove imaging powders. The first null hypothesis of this study was rejected; there was a significant difference in bond strength of resin cement to dentin based on rinse, though not the duration of the rinse. The results of this study suggest that a rinse time of ≥1 second is sufficient to remove imaging powder residue. However, a rinse time of 0 (the nonrinsed groups) displayed General Dentistry January/February 2015 75 Dental Materials Effect of imaging powders on the bond strength of resin cement significantly lower bond strengths. The failure mode for the nonrinsed groups was almost entirely adhesive fracture, suggesting a weaker interface, while the 1- and 10-second rinse groups primarily displayed adhesive and mixed fractures, which was similar to the control group. The second null hypothesis was not rejected in this study. There was not a significant difference in bond strength of resin cement to dentin based on the type of powder despite the fact that the 3 imaging powders differed greatly. While Optispray is a self-contained propellant, CEREC Powder is applied with a delivery unit such as the PowderPro after the application of a glycerin coating.34,35 Occlude has not been marketed as an imaging powder and contains magnesium stearate instead of titanium dioxide as found in traditional imaging powders.33 Occlude was utilized in this study as it has been considered an economical alternative to existing imaging powders. This study did not attempt to evaluate Occlude as an imaging powder and cannot make any conclusion as to its efficacy for that purpose. Future research could focus on magnesium stearate reflectivity on preparation surfaces and margins. Self-adhesive resin cements such as Unicem do not require an acid-etch step prior to bonding.36 When using etch-andrinse type resin cements, imaging powder may be removed more thoroughly than with self-adhesive cements. Remaining residue was observed to result in more adhesive-type failures. The dentin surfaces tested were relatively flat, but roughened with a diamond bur to simulate intraoral tooth preparation. Clinically, less efficient powder removal may be encountered when rinsing 3-dimensional preparations (with vertical surfaces and more box-like forms). However, treating the surfaces with flour of pumice and prophy cup prior to cementation would likely further reduce remnants of imaging powder. Conclusion The CAD/CAM imaging powders did not affect the shear bond strength of the self-adhesive resin cement to dentin if the powders were rinsed with water. This study showed that the manufacturers’ instructions, while nonspecific, were 76 January/February 2015 adequate for removal of the 3 tested powders. The amount of residue that remained after rinsing with water did not significantly affect bond strength. Author information Maj Jordan is a general dentist at Shaw AFB, SC, Lt Col Bailey is the director of Senior Resident Education and Training, Lt Col Ashcraft-Olmscheid is the director of Prosthodontics Education, and Col (ret) Vandewalle is the director of Dental Research, Advanced Education in General Dentistry Residency, US Air Force Postgraduate Dental School, JBSA-Lackland, Texas and Uniformed Services University of the Health Sciences, Bethesda, Maryland. Disclaimer The views expressed in this study are those of the authors and do not reflect the official policy of the United States Air Force, the Department of Defense, or the United States Government. The authors do not have any financial interest in the companies whose materials are discussed in this article. References 1. Birnbaum NS, Aaronson HB. Dental impressions using 3D digital scanners: virtual becomes reality. Compend Contin Educ Dent. 2008;29(8):494, 496, 498-505. 2. Christensen GJ. Impressions are changing: deciding on conventional, digital or digital plus in-office milling. J Am Dent Assoc. 2009;140(10):1301-1304. 3. Bernhart J, Brauning A, Altenburger MJ, Wrbas KT. Cerec3D endocrowns—two-year clinical examination of CAD/CAM crowns for restoring endodontically treated molars. Int J Comput Dent. 2010;13(2):141-154. 4. Patel N. Integrating three-dimensional digital technologies for comprehensive implant dentistry. J Am Dent Assoc. 2010;141(Suppl 2):20S-24S. 5. Giordano R. Materials for chairside CAD/CAM-produced restorations. J Am Dent Assoc. 2006;137(Suppl): 14S-21S. 6. Fasbinder DJ. Materials for chairside CAD/CAM restorations. Compend Contin Educ Dent. 2010;31(9):702704, 706, 708-709. 7.Fasbinder DJ. The CEREC system: 25 years of chairside CAD/CAM dentistry. J Am Dent Assoc. 2010; 141(Suppl 2):3S-4S. 8. Fasbinder DJ, Dennison JB, Heys D, Neiva G. A clinical evaluation of chairside lithium disilicate CAD/CAM crowns: a two-year report. J Am Dent Assoc. 2010; 141(Suppl 2):10S-14S. 9. Fasbinder DJ, Poticny DJ. Accuracy of occlusal contacts for crowns with chairside CAD/CAM techniques. Int J Comput Dent. 2010;13(4):303-316. 10. FasbinderDJ. Clinical performance of chairside CAD/ CAM restorations. J Am Dent Assoc. 2006;137(Suppl): 22S-31S. General Dentistry www.agd.org 11. Fasbinder DJ, Dennison JB, Heys DR, Lampe K. The clinical performance of CAD/CAM-generated composite inlays. J Am Dent Assoc. 2005;136(12):1714-1723. 12. Fasbinder DJ. Restorative material options for CAD/ CAM restorations. Compend Contin Educ Dent. 2002; 23(10):911-916, 918, 920, passim. 13. Griggs JA. Recent advances in materials for all-ceramic restorations. Dent Clin North Am. 2007;51(3):713727, viii. 14. Reich S, Hornberger H. The effect of multicolored machinable ceramics on the esthetics of all-ceramic crowns. J Prosthet Dent. 2002;88(1):44-49. 15. Sulaiman F, Chai J, Jameson LM, Wozniak WT. A comparison of the marginal fit of the In-Ceram, IPS Empress, and Procera crowns. Int J Prosthodont. 1997; 10(5):478-484. 16. Kassem AS, Atta O, El-Mowafy O. Combined effects of thermocycling and load-cycling on microleakage of computer-aided design/computer-assisted manufacture molar crowns. Int J Prosthodont. 2011;24(4):376-378. 17.El-Badrawy W, Hafez RM, El Naga AI, Ahmed DR. Nanoleakage of self-adhesive resin cements used in bonding CAD/CAM ceramic material to dentin. Eur J Dent. 2011;5(3):281-290. 18. Bernhart J, Schulze D, Wrbas KT. Evaluation of the clinical success of CEREC 3D inlays. Int J Comput Dent. 2009;12(3):265-277. 19. Boening KW, Wolf BH, Schmidt AE, Kastner K, Walter MH. Clinical fit of Procera AllCeram crowns. J Prosthet Dent. 2000;84(4):419-424. 20. Hickel R, Manhart J. Longevity of restorations in posterior teeth and reasons for failure. J Adhes Dent. 2001; 3(1):45-64. 21. Isenberg BP, Essig ME, Leinfelder KF. Three-year clinical evaluation of CAD/CAM restorations. J Esthet Dent. 1992;4(5):173-176. 22. Martin N, Jedynakiewicz NM. Clinical performance of CEREC ceramic inlays: a systematic review. Dent Mater. 1999;15(1):54-61. 23. Magne P, Schlichting LH, Paranhos MP. Risk of onlay fracture during pre-cementation functional occlusal tapping. Dent Mater. 2011;27(9):942-947. 24. Magne P, Paranhos MP, Schlichting LH. Influence of material selection on the risk of inlay fracture during pre-cementation functional occlusal tapping. Dent Mater. 2011;27(2):109-113. 25. Ozturk AN, Inan O, Inan E, Oztürk B. Microtensile bond strength of cad-cam and pressed-ceramic inlays to dentin. Eur J Dent. 2007;1(2):91-96. 26. Hill EE, Lott J. A clinically focused discussion of luting materials. Aust Dent J. 2011;56(Suppl 1):67-76. 27. Kitayama S, Pilecki P, Nasser NA, et al. Effect of resin coating on adhesion and microleakage of computeraided design/computer-aided manufacturing fabricated all-ceramic crowns after occlusal loading: a laboratory study. Eur J Oral Sci. 2009;117(4):454-462. 28. Poticny DJ, Klim J. CAD/CAM in-office technology: innovations after 25 years for predictable, esthetic outcomes. J Am Dent Assoc. 2010;141(Suppl 2):5S-9S. 29. Hembree JH Jr. Comparisons of fit of CAD-CAM restorations using three imaging surfaces. Quintessence Int. 1995;26(2):145-147. 30. Lenzen A. The use of ScanWhite: an alternative to Cerec powder. Int J Comput Dent. 1999;2(1):61-63. 31. da Costa JB, Pelogia F, Hagedorn B, Ferracane JL. Evaluation of different methods of optical impression making on the marginal gap of onlays created with CEREC 3D. Oper Dent. 2010;35(3):324-329. 32. Trifkovic B, Todorovic A, Lazic V, Draganjac M, Mirkovic N, Jokic B. Accuracy of optical scanning methods of the CEREC 3D system in the process of making ceramic inlays [in Serbian]. Vojnosanit Pregl. 2010; 67(10): 812-818. 33. Pascal International, Inc. Occlude [product information]. Available at: http://www.pascalinternational.net/ Products/48-occlude.aspx. Accessed November 6, 2014. 34. Vident. VITA CEREC Powder [product information]. Available at: http://www.pascalinternational.net/ Products/48-occlude.aspx. Accessed November 6, 2014. 35. Sirona Dental Inc. USA. CEREC Optispray [product information]. Available at: http://www.sironausa.com/ us/products/digital-dentistry/cad-cammaterials/?tab=3095. Accessed November 6, 2014 36. 3M ESPE RelyX Unicem [product information]. Available at: http://solutions.3mae.ae/wps/portal/3M/en_ AE/3M_ESPE/Dental-Manufacturers/Products/ Dental-Indirect-Restorative/Dental-Cement/Self-Adhesive-Cement/. Accessed November 6, 2014. 37. Burgess JO, Ghuman T, Cakir D. Self-adhesive resin cements. J Esthet Restor Dent. 2010;22(6):412-419. 38. Ferracane JL, Stansbury JW, Burke FJ. Self-adhesive resin cements - chemistry, properties and clinical considerations. J Oral Rehabil. 2011;38(4):295-314. 39. Frankenberger R, Lohbauer U, Schaible RB, Nikolaenko SA, Naumann M. Luting of ceramic inlays in vitro: marginal quality of self-etch and etch-and-rinse adhesives versus self-etch cements. Dent Mater. 2008; 24(2):185-191. Manufacturers Advanced Dental Instruments LLC, Haworth, NJ 201.384.1979 Align Technology, Inc., San Jose, CA 800.577.8767, www.itero.com Brasseler USA, Savannah, GA 800.841.4522, www.brasselerusa.com Buehler, Lake Bluff, IL 800.283.4537, www.buehler.com Dentaco As, Haukeland, Norway 47.5525.4090, www.dentaco.no Hi-Tec Dental Products, Inc., Lenoir City, TN 800.859.2006, www.hi-tecdental.com Instron Corp., Norwood, MA 800.877.6674, www.instron.com Ivoclar Vivadent, Inc., Amherst, NY 800.533.6825, www.ivoclarvivadent.us Kerr Corporation, Orange, CA 800.537.7123, www.kerrdental.com Nikon USA, Melville, NY 631.547.4200, www.nikonusa.com Pascal International, Inc., Bellevue, WA 800.426.8051, www.pascalinternational.net Planmeca E4D Technologies, Richardson, TX 972.234.3380, www.e4D.com Sirona Dental Systems, Inc., Charlotte, NC 800.659.5977, www.sironausa.com Ultradent Products, Inc., South Jordan, Utah 888.230.1420, www.ultradent.com Vident, Brea, CA 800.828.3839, www.vident.com 3M ESPE, St. Paul, MN 800.634.2249, solutions.3m.com www.agd.org There is another article on DENTAL MATERIALS in the online edition. •Impact of toothbrushing with a dentifrice containing calcium peroxide on enamel color and roughness Visit www.agd.org/GeneralDentistry General Dentistry January/February 2015 77 Implant Maintenance Crestal approach for removing a migrated dental implant from the maxillary sinus: a case report Raid Sadda, DDS, MS, MFDRCSI This article reports a rare case of a horizontally displaced dental implant that migrated into the maxillary sinus 6 months after 3 implants were inserted into the augmented maxillary posterior region. Migration of dental implants into the maxillary sinus usually occurs during surgery and can result in serious complications. W hile dental implants have revolutionized the practice of modern dentistry, they can also be problematic, especially when placed in the posterior maxilla. Implants in this area have an increased risk for failure because of low bone density and shortness of the alveolar ridge.1 The reasons dental implants may migrate into the maxillary sinus are the lack of initial stability during the surgery, poor bone quality, or—the most common factor—local tissue infection around the implant.1 The surgeon must be able to manage problems that arise intraoperatively as well as those that develop postoperatively. Case report A 55-year-old man was referred to a private dental office to have implants placed in the maxillary posterior edentulous area. Pantomograph and periapical radiographs showed a large radiolucent lesion at the periapical areas of the nonrestorable maxillary first and second right premolars; the lesion extended to the maxillary sinus (Fig. 1). A computed tomography scan confirmed the diagnosis (Fig. 2). After local anesthesia was administered, the premolars were removed and the large lesion enucleated completely from the maxilla and maxillary sinus by separating the maxillary sinus mucosa from the cystic lining. The lesion was sent for histopathologic analysis and it was determined to be a radicular dental cyst. The remaining space was filled with a corticocancellous bone graft which was extended to fill part of the maxillary sinus. In addition, a nonresorbable membrane was placed over the bone graft. No evidence of recurrence was observed 6 months postsurgery. 78 January/February 2015 Received: February 21, 2013 Accepted: June 24, 2013 Key words: radicular cyst, maxillary sinus augmentation, removal of migrated dental implant Under local anesthesia, 3 machined implants were then placed at the site of the first molar and 2 premolars with initial stability. A radiograph taken 1 week postimplantaion confirmed the stability of the implants (Fig. 3). A radiograph taken 5 months later revealed a horizontal migration of the implant from the site of the first molar into the maxillary sinus (Fig. 4). Local anesthesia was administered through a crestal incision, a mucoperiostal flap was raised, and part of the crestal bone was removed (Fig. 5). At this point, the migrated implant was seen at the floor of the sinus (Fig. 6). The implant was grasped with a hemostat and removed from the sinus. The space remaining was irrigated; a collagen membrane was placed over the mucosa, and a corticocancellous bone graft was placed and covered with a nonresorbable membrane. The wound was closed with chromic gut sutures. Postoperative prescription and instructions were given. The patient tolerated the procedure well, with minimal facial swelling and pain. 2 clinical cases involving intraosseous apical movement of an implant several years after placement.4 According to Pagella et al, the incidence of metallic foreign bodies in the maxillary sinus has increased following the development of osseointegrated implants to treat edentulous cases.5 A 2000 article recommended immediate removal of failed implants that have migrated into the maxillary sinus.6 The real reasons why dental implants migrate from their initial placement toward the maxillary sinus are unknown. This migration may be a technical issue related to poor surgical preparation, drilling, or implant placement. Lack of bone thickness/density of an edentulous posterior maxillary segment has been proposed as an explanation for inadequate implant stability and anchorage. Previously reported cases of dental implant migration indicated that Discussion Implants placed in the posterior maxilla can fail due to the low density of the bone in that area. There are a few reports in the literature involving dental implants migrating into the maxillary sinus.1-6 A 1992 article by Ueda & Kaneda reported a case of maxillary sinusitis caused by a displaced connection screw 2 months after implant placement.1 Quiney et al reported a case of implant displacement 2 weeks postinsertion.2 More recently, Haben et al reported the displacement of a dental implant into the ethmoid sinus.3 A 2005 article by Galindo et al reported General Dentistry www.agd.org Fig. 1. A preoperative radiograph showing a periapical lesion at the maxillary second premolar and a root lesion at the mesial of the maxillary first premolar. Fig. 2. A computed tomography scan confirming the presence of a periapical lesion. Fig. 3. A radiograph taken 1 week after the insertion of 3 implants. Fig. 4. A radiograph taken 5 months postimplantation demonstrating the migration of the implant into the maxillary sinus. migrations may have been caused by the dentist’s surgical technique, by an alveolar infection or lesion that resulted in bone destruction, or by a particular bone weakness, such as osteoporosis or osteopenia.2,6 Various mechanisms have been proposed to explain the migration of an implant into the maxillary sinus.7 These mechanisms can include changes in intrasinal and nasal pressures, an autoimmune reaction to the implant (resulting in periimplant bone destruction and compromised osseointegration), and resorption produced by an incorrect distribution of occlusal forces.7 In the present case, the implant migrated without being subjected to occlusal forces, as the bone depth prevented integration of the implant prior to second stage surgery. Bone loss in the augmented area led to implant failure. The most common approach for removing implants that have migrated into the maxillary sinus involves a lateral-wall osteotomy; however, because the migrated implant in the present case was close to the Fig. 5. A crestal incision made to approach the implant at the floor of the maxillary sinus. floor of the maxillary sinus, an alternative crestal approach was used.8 This approach is minimally destructive to the maxillary sinus, while reducing the risk of injury to the maxillary artery (which is located at the lateral wall of the maxillary sinus). Conclusion Placing an implant in the posterior maxilla—with or without sinus grafting—can offer a reasonably good prognosis; however, the procedure is not free of complications. An implant in a grafted area may increase both the risk of implant failure and migration to the maxillary sinus. To decrease the risk of migration and complications, the dentist should carefully study the radiographs before the second stage of implant surgery in order to be aware of the quality of the bone, implant stability, and the proper surgical technique indicated. Author information Dr. Sadda is a clinical associate professor, Department of Oral and Maxillofacial www.agd.org Fig. 6. The implant prior to removal by a hemostat. Surgery, New York University, New York, and an attending oral surgeon, St. Barnabas Hospital, Bronx, New York. References 1. Ueda M, Kaneda T. Maxillary sinusitis caused by dental implant: report of two cases. J Oral Maxillofac Surg. 1992:50(3):285-287. 2. Quiney RE, Brimble M, Hodge M. Maxillary sinusitis from dental osseointegrated implants. J Laryngol Otol. 1990;104(4):333-334. 3. Haben CM, Balys R, Frenkiel S. Dental implant migration into the Ethmoid sinus. J Otolaryngol. 2003;32(5): 342-344. 4. Galindo P, Sanchez-Fernandez E, Avila G, Cutando A, Fernandez JE. Migration of implants into the maxillary sinus: two clinical cases. Int J Oral Maxillofac Implants. 2005;20(2):291-295. 5. Pagella F, Emanuelli E, Castelnuovo P. Endoscopic extraction of a metal foreign body from the maxillary sinus. Laryngoscope. 1999:109(2 Pt 1);339-342. 6. Iida S, Tanaka N, Kogo M, Matsuya T. Migration of a dental implant into the maxillary sinus. A case report. Int J Oral Maxillofac Surg. 2000;29(5):358-359. 7. Regev E, Smith RA, Perrott DH, Pogrel MA. Maxillary sinus complications related to endosseous implants. Int J Oral Maxillofac Implants. 1995;10(4):451-461. 8. Akira Kitamura. Removal of a migrated dental implant from a maxillary sinus by transnasal endoscopy. Br J Oral Maxillofac Surg. 2007;45(5):410-411. General Dentistry January/February 2015 79 Answers Self-Instruction Exercise No. 343 January/February 2014, p. 42 1. B 5. C 9. C 13. B 2. D 6. C 10. D 14. D 3. A 7. A 11. C 15. A 4. D 8. D 12. A Exercise No. 344 January/February 2014, p. 61 1. B 5. C 9. B 13. B 2. C 6. A 10. A 14. A 3. B 7. C 11. B 15. D Advertisers Index If you would like more information about the companies who advertised in this issue of General Dentistry, please contact: CompanyPage Blue Sky Bio....................................................................... Inside front www.BlueSkyBio.comcover California Implant Institute.........................................3 858.496.0574 www.implanteducation.net Glidewell Laboratories..................................................Back cover 800.521.0126 www.glidewelldental.com Texas A&M University....................................................13 Baylor College of Dentistry 214.828.8100 www.tambcd.edu We try to present an accurate index. Occasionally, this is not possible because of a last minute change. 80 January/February 2015 General Dentistry www.agd.org 4. A 8. B 12. B Exercise No. 345 January/February 2014, p. 73 1. C 5. B 9. C 13. C 2. D 6. C 10. C 14. B 3. B 7. C 11. B 15. A 4. D 8. B 12. D Answer Sheet AGD/ADA ID: ___________________________________________________________ First name: ___________________________________________ Middle initial: _______ Last name: _________________________________________________________ Address 1: _______________________________________________________________________________________________________________________________ Address 2: _______________________________________________________________________________________________________________________________ City: _______________________________________________________ State/Province: ______________________ ZIP/Postal code: ______________________________ PAYMENT Currently enrolled in Self-Instruction Enrolling today I am paying by: Check (Payable to AGD) Credit Card (Complete payment information) Select the number of exercises you wish to purchase: AGD Member Non-member 1 Exercise................. $30................. $50 2 Exercises............... $50................. $75 3 Exercises............... $60................. $90 6 Exercises............... $100............... $150 Credit Card Number: ___________________________________________________ Expiration Date: _______________ Signature: ______________________________________________________________________________________ ANSWERS Select the best answer by completely filling in one box for each response. Correct Incorrect A Incorrect A A Best Value! 12 Exercises............. $150............... $225 Exercise No. Each exercise is worth 2 CE credits. Exercise No. 361 Exercise No. 362 363 A B C D A B C D 111 A B C D A B C D 222 A B C D A B C D 333 A B C D A B C D 444 A B C D A B C D 555 A B C D A B C D 666 A B C D A B C D 777 A B C D A B C D 888 A B C D A B C D 999 A B C D A B C D 101010 A B C D A B C D 111111 A B C D A B C D 121212 A B C D A B C D 131313 A B C D A B C D 141414 A B C D A B C D 151515 A B C D This form can be submitted via mail or fax. A B C D A B C D Self-Instruction312.440.4261 Academy of General Dentistry 560 W. Lake St., Sixth Floor Chicago, IL 60661-6600 A B C D A B C D A B C D A B C D Answers can also be submitted online. www.agd.org A B C D A B C D A B C D For more information, contact Kris Abed-Canchola at 888.AGD.DENT (888.243.3368), ext. 4336, or at [email protected]. A B C D A B C D A B C D A B C D Please allow 2 weeks for credit to be awarded. A B C D EVALUATION Please respond to the statements below, using the following scale: 1 Poor; 2 Below average; 3 Average; 4 Above average; 5 Excellent Exercise No. Exercise No. 361 Practicality of the content................................................................. Benefit to your clinical practice........................................................ Quality of illustrations........................................................................ Clarity of objectives............................................................................. Clarity of exercise questions............................................................. Relevance of exercise questions....................................................... Did this exercise achieve its objectives?......................................... Did this article present new information?..................................... How much time did it take you to complete this exercise?........ Exercise No. 362 363 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 YesNo YesNo __________mins Yes No Yes No __________ mins Deadline for submission of answers to Exercises 361-363 is December 31, 2015. YesNo YesNo _________ mins Cancer Screening Ameloblastic carcinoma of the mandible manifesting as an infected odontogenic cyst Adepitan A. Owosho, BChD n Anitha Potluri, DMD n Richard E. Bauer III, DMD, MD n Elizabeth A. Bilodeau, DMD, MD, MSEd Ameloblastic carcinoma (AC) is a rare malignant odontogenic tumor. Although most ACs appear to originate de novo, some cases originate from a pre-existing ameloblastoma. This article presents the case of a 69-year-old man with an AC in the left body of the mandible. Radiographically, the lesion resembled an odontogenic cyst surrounding an impacted tooth. While ACs tend to have aggressive features that A n ameloblastic carcinoma (AC) is a rare malignant odontogenic tumor with a reported incidence of 1%-3%.1-4 In 1984, Slootweg & Muller proposed that the term ameloblastic carcinoma should be used to designate lesions that exhibit features of both ameloblastoma and carcinoma in either primary and/or metastatic lesions.5 Most ACs are presumed to originate de novo, with some cases involving the malignant transformation of a pre-existing ameloblastoma.6 In 2005, the World Health Organization classified AC into 3 types: primary, secondary (intraosseous), and secondary (peripheral).7 A 2009 study by Yoon et al reported 6 new cases of AC.8 At that time, there were 104 cases in the English literature; since then, several other cases have been reported.8-11 The age of AC manifestation ranges from 7 to 91 years with an average age of 53, although it is most frequently found in patients after age 60, with a 2:1 maleto-female predilection.9-11 The mandible is involved more commonly than the maxilla, with a posterior predilection, although a rare case involving the anterior skull base was reported in 2005.12 AC has aggressive clinical features, such as pain, expansion of the jaw, and perforation of the cortex. It also may metastasize; although the regional lymph nodes are the most common site, distant metastases to the lungs, brain, and liver have been reported.8,9,13-21 In most cases, radiographic findings reveal an ill-defined radiolucency, often with scattered sites of focal radiopaque dystrophic calcification.11,14,15,19,22 Wide local resection (resulting in a tumor-free margin of 10-15 mm) is thought to be the treatment of choice; distinguish them from their benign counterparts, some are more subtle in their presentation. Therefore, it is important that dentists rule out malignancy in lesions that do not display obvious radiographic features. Received: April 8, 2013 Accepted: July 3, 2013 although adjuvant radiation and/or chemotherapy and regional lymph node dissection have also been considered.6,23 This article presents a case involving the diagnosis and treatment of an AC. Case report A 69-year-old man was referred to the Department of Oral and Maxillofacial Surgery at the School of Dental Medicine of the University of Pittsburgh, Pennsylvania for evaluation and definitive management of an impacted left mandibular third molar, which had been symptomatic for 2 months. The patient stated that he had developed pain and an infection in the lower left mandible. He had previously sought treatment from his general dentist, who treated him with a course of antibiotics. The patient presented with periapical radiographs taken by the referring dentist. A panoramic radiograph was obtained for further evaluation (Fig. 1). The radiographs revealed a full bony impaction of tooth No. 17, which was distoangularly positioned. There was a uniform and mildly enlarged radiolucent follicular space from the superior part of the crown to the inferior and apical part of the tooth. Expansion was noted toward the inferior alveolar (IA) canal, pushing the IA in an inferior direction, with associated erosion in the superior cortex of the IA canal. Mild sclerosis was noted at the posterior extent of the follicular lining and inferiorly within the radiolucency. A radiolucency was also noted within the tooth coronally, consistent with internal resorption. No lamina dura or follicle lining was noted Fig. 1. Preoperative panoramic radiograph of a 69-year-old man with an impacted left mandibular third molar and inferior expansion of a lesion. www.agd.org General Dentistry January/February 2015 e1 Cancer Screening Ameloblastic carcinoma of the mandible manifesting as an infected odontogenic cyst Fig. 2. A photomicrograph of the patient, showing a tumor island with comedonecrosis. (H&E, magnification 200X). apically. Based on these findings, an initial diagnosis of an impacted tooth with inflammation or a secondarily infected cystic lesion was made. The left mandibular third molar was extracted and an excisional biopsy was performed on the associated lesion. The histopathologic findings revealed odontogenic tumor islands within a fibrous stroma, exhibiting peripheral palisading with nuclear polarization away from the basement membrane. The central cells were loose and discohesive, recapitulating stellate reticulum. However, the sections showed increased mitotic activity, necrosis, and varying nuclear size, shape, and staining (Fig. 2 and 3). No angiolymphatic or perineural invasion was present. A Ki-67 stain—a proliferative immunoperoxidase marker—showed an elevated percentage of positive cells (Fig. 4). The histologic sections, in conjunction with immunophenotypic studies, supported the diagnosis of AC. The patient returned for a follow-up visit 1 week postsurgery; at that time, a cone beam computed tomography (CBCT) scan was taken. It revealed an ill-defined radiolucency with areas of focal radiopacities and cortical disruption, consistent with postoperative surgical margins and the aggressive nature of the lesion (Fig. 5). To investigate the presence of the lesion in regional lymph nodes (as well as e2 January/February 2015 Fig. 3. A photomicrograph of the patient, showing a tumor island with an increased number of mitotic figures. (H&E, magnification 400X). Fig. 4. A photomicrograph of the patient showed increased positive staining, indicating a high proliferative index. (Ki-67, magnification 400X). Fig. 5. A postextraction CBCT scan. distant metastases), a fluorodeoxyglucose (FDG)-positron emission tomography image was performed, revealing elevated FDG uptake only in the left mandible. There was no abnormal high uptake anywhere else, suggesting no regional or distant metastases. General Dentistry www.agd.org Wide local resection of hard and soft tissue was planned. One month after the initial biopsy, the patient underwent resection of the left mandible and reconstruction with a secondary titanium reconstruction bar. This bar was used to replate the mandible. Prior to surgery, Fig. 6. An intraoperative image of the patient 1 month postsurgery, after placement of a secondary reconstruction bar. a stereolithic model was fabricated and the secondary reconstruction bar was pre-bent. Intraoperatively, 15 mm margins were identified and 41 mm of bone and tissue were resected from the left mandible (Fig. 6 and 7). The overlying periosteum and submucosa were removed. Full thickness mucosa and submucosa was resected at the site of the extraction and biopsy. The resulting orocutaneous communication was closed primarily. A silastic block was inserted to maintain space for future osseous reconstruction. The resected segment was sent to the pathology department for definitive histological examination. The previous diagnosis of AC was confirmed; however, the anteromedial overlying submucosa demonstrated 2 islands of tumor. Due to these positive margins, a wide local resection with a selective neck dissection and postoperative radiation therapy was planned. The subsequent specimen had negative margins with no nodal involvement. Discussion AC is a rare malignant odontogenic tumor, which is treated by wide surgical resection with consideration for the possibility of adjuvant radiation and/or chemotherapy. Typically, cases of AC treated using conservative therapy have a high rate of recurrence and death.9 Fig. 7. Photograph of the 41 mm of bone and soft tissue resected surgically at the 1-month follow-up visit. The clinical symptoms of AC are more aggressive than those of its benign counterpart, ameloblastoma. However, in the present case, the patient’s only symptom was pain of approximately 2 months duration, persisting even after treatment with antibiotics. The radiographic features of the present case were subtle, including mild enlargement of the follicular space, pushing of the IA canal inferiorly, and erosion of the superior cortex, leading to a diagnosis of either an impacted tooth with inflammation or a secondarily infected cystic lesion. In retrospect, these seemingly subtle features reflected an aggressive lesion. Conclusion This article presents a case of a mandibular AC with an impacted third molar exhibiting subtle cystic radiographic features and mildly aggressive qualities. This case indicates that even though most ACs have aggressive features delineating them from their benign counterparts, some can appear subtle. Thus, care has to be taken to rule out malignancy in lesions with subtle radiographic features. Author information Dr. Owosho is the chief resident, Oral and Maxillofacial Pathology, Department of Diagnostic Sciences, School of Dental Medicine, University of Pittsburgh, Pennsylvania, where Drs. Potluri www.agd.org and Bilodeau are assistant professors, and Dr. Bauer is an assistant professor with the Department of Oral and Maxillofacial Surgery. References 1. Ladeinde al, Ajayi OF, Ogunlewe MO, et al. Odontogenic tumors: a review of 319 cases in a Nigerian teaching hospital. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2005;99(2):191-195. 2. Taghavi N, Mehrdad L, Rajabi M, Akbarzadeh A. A 10-year retrospective study on malignant jaw tumors in Iran. J Craniofac Surg. 2010;21(6):1816-1819. 3. Jing W, Xuan M, Lin Y. Odontogenic tumours: a retrospective study of 1642 cases in a Chinese population. Int J Oral Maxillofac Surg. 2007;36(1):20-25. 4. Abiko Y, Nagayasu H, Takeshima M, et al. Ameloblastic carcinoma ex ameloblastoma: report of a case-possible involvement of CpG island hypermethylation of the p16 gene in malignant transformation. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2007;103(1):72-76. 5. Slootweg PJ, Muller H. Malignant ameloblastoma or ameloblastic carcinoma. Oral Surg Oral Med Oral Pathol. 1984;57(2):168-176. 6. Suomalainen A, Hietanen J, Robinson S, Peltola JS. Ameloblastic carcinoma of the mandible resembling odontogenic cyst in a panoramic radiograph. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2006;101(5): 638-642. 7. Barnes L, Eveson JW, Reichart P, Sidransky D, eds. World Health Organization Classification of Tumours: Head and Neck Tumours. Lyon, France: IARC Press; 2005. 8. Yoon, HJ, Hong SP, Lee JI, Lee SS, Hong SD. Ameloblastic carcinoma: an analysis of 6 cases with review of the literature. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2009;108(6):904-913. 9. Hall JM, Weathers DR, Unni KK. Ameloblastic carcinoma: an analysis of 14 cases. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2007;103(6):799-807. General Dentistry January/February 2015 e3 Cancer Screening Ameloblastic carcinoma of the mandible manifesting as an infected odontogenic cyst 10. Carnelio S, Solomon M, Manohar V. Ameloblastic carcinoma. A case report with review of literature. Indian J Dent Res. 2001;12(4):238-241. 11. Matsuzaki H, Katase N, Hara M, et al. Ameloblastic carcinoma: a case report with radiological features of computed tomography and magnetic resonance imaging and positron emission tomography. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2011;112(1):e40e47. 12. Ozlugedik S, Ozcan M, Basturk O, et al. Ameloblastic carcinoma arising from anterior skull base. Skull Base. 2005;15(4):269-272. 13. Akrish S, Buchner A, Shoshani Y, Vered M, Dayan D. Ameloblastic carcinoma: report of a new case, literature review, and comparison to ameloblastoma. J Oral Maxillofac Surg. 2007;65(4):777-783. 14. Avon SL, McComb J, Clokie C. Ameloblastic carcinoma: case report and literature review. J Can Dent Assoc. 2003;69(9):573-576. 15. Benlyazid A, Lacroix-Triki M, Aziza R, Gomez-Brouchet A, Guichard M, Sarini J. Ameloblastic carcinoma of the maxilla: case report and review of the literature. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2007; 104(6):e17-e24. 16. Dhir K, Sciubba J, Tufano RP. Ameloblastic carcinoma of the maxilla. Oral Oncol. 2003;39(7):736-741. e4 January/February 2015 17. Jindal C, Palaskar S, Kaur H, Shankari M. Low-grade spindle-cell ameloblastic carcinoma: report of an unusual case with immunohistochemical findings and review of the literature. Curr Oncol. 2010;17(5):52-57. 18. Goldenberg D, Sciubba J, Koch W, Tufano RP. Malignant odontogenic tumors: a 22-year experience. Laryngoscope. 2004;114(10):1770-1774. 19. Bruce RA, Jackson IT. Ameloblastic carcinoma. Report of an aggressive case and review of the literature. J Craniomaxillofac Surg. 1991;19(6):267-271. 20. Simko EJ, Brannon RB, Eibling DE. Ameloblastic carcinoma of the mandible. Head Neck. 1998;20(7):654659. 21. Infante-Cossio P, Hernandez-Guisado JM, FernandezMachin P, Garcia-Perla A, Rollon-Mayordomo A, Gutierrez-Perez JL. Ameloblastic carcinoma of the maxilla: a report of 3 cases. J Craniomaxillofac Surg. 1998; 26(3):159-162. 22. Verneuil A, Sapp P, Huang C, Abemayor E. Malignant ameloblastoma: classification, diagnostic, and therapeutic challenges. Am J Otolaryngol. 2002;23(1):4448. 23. Zwahlen RA, Gratz KW. Maxillary ameloblastomas: a review of the literature and of a 15-year database. J Craniomaxillofac Surg. 2002;30(5):273-279. General Dentistry www.agd.org Surgical Orthodontics A large dentigerous cyst treated with decompression and orthosurgical traction: a case report Rodrigo Dias Nascimento, PhD n Fernando Vagner Raldi, PhD n Michelle Bianchi de Moraes, PhD n Paula Elaine Cardoso, PhD Deborah Holleben, DDS This article presents the case of an 8-year-old patient who presented with a large radiolucency associated with the maxillary left canine and a supernumerary tooth. A computed tomography scan showed the radiolucency was in close proximity to the roots of the anterior teeth, with no areas of root resorption, and expansion into the left maxillary sinus. The boundaries of the maxillary sinus floor were still preserved. After positive aspiration of intralesional liquid and due to the large size of the radiolucency, a decompression technique was selected to preserve the permanent canine. Surgery was performed to remove the supernumerary tooth, followed by A mong developmental odontogenic cysts, dentigerous cysts are the most common; 20% of the epithelial cysts in gnathic bones are dentigerous.1 The dentigerous cyst originates at the separation of the follicle that lies around the crown of an impacted tooth, binding to the crown’s cementoenamel junction.1 Its pathogenesis is unknown; however, it has been suggested that it progresses through an accumulation of fluid between the reduced enamel epithelium and the tooth crown.1 Dentigerous cysts are primarily found in children and adolescents (most frequently as a cystic lesion), although there is a high incidence rate in the second and third decades of life and a predilection for men and Caucasians.2 Dentigerous cysts in Fig. 1. Clinical examination revealing a vestibular bulging in the region of the maxillary left canine. orthodontic treatment and surgery to allow access for orthodontic traction of the permanent canine. More than 5 years post-treatment, no recurrence was observed and the therapeutic option to position and preserve the permanent canine was successful. Received: May 14, 2013 Accepted: July 23, 2013 Key words: dentigerous cyst, decompression, eruption of teeth, unerupted maxillary canine children may expand, causing retention of the involved dental element and deformation of the surrounding alveolar bone (with or without bone cortical expansion or displacement of dental roots and adjacent anatomical structures). Due to their slow and expansive evolution, these cysts essentially are asymptomatic; as a result, diagnoses are often due to radiographic findings.3 Facial asymmetry may result from extensive injuries, although large dentigerous cysts are rare, and lesions supposedly diagnosed on the radiographic examination as large dentigerous cysts are revealed at the histopathological examination as keratocystic odontogenic tumors or ameloblastomas.1 Symptomatic lesions are generally the result of periapical inflammation of an overlying primary tooth, a periodontal lesion that affects an adjacent tooth, or a bone break that causes disruption in communication with the oral cavity, nasal cavity, or maxillary sinuses.1 It appears radiographically as a radiolucent area, unilocular with a well-defined and usually sclerotic margin, associated with the crown of an included tooth. In order to differentiate a small dentigerous cyst from an enlarged dental follicle (which also is located above an included tooth), it has been suggested that the typical space around the crown of an included tooth is approximately 3-4 mm in diameter.1 In histopathologic analysis, a dental follicle surrounding the crown of an included tooth appears as a thin layer of reduced enamel epithelium, thus making it difficult www.agd.org to distinguish between such a follicle and a small dentigerous cyst.1 Furthermore, cystic epithelium has metaplasia that is similar to oral mucosa epithelium.3 The epithelial lining of a dentigerous cyst consists of 2-4 layers of nonkeratinized flattened cells, with a flat interface between the epithelium and connective tissue.1 The capsule of fibrous connective tissue is arranged loosely and contains an amorphous substance consisting of glycosaminoglycans, possibly accompanied by small islands and strands of odontogenic epithelial rests with an inactive aspect.1 For large cysts, marsupialization and decompression often are indicated as alternative therapies.3 These procedures simplify the surgical procedure, assist in the eruption of the involved tooth, and minimize any adverse consequences.3 The subsequent new bone formation after these procedures results in the decrease of the peripheral lesion size and directs the eruption of the involved tooth.3 This article analyzes a clinical decompression technique associated with surgical orthodontic treatment and its efficacy in treating extensive lesions, allowing for the regeneration of bone defects and preservation of the included dental element—resulting in its eruption in the oral cavity. Case report An orthodontist referred an 8-year-old boy with vestibular bulging in the region of the maxillary left primary canine. The mucosa had a normal appearance and there were no symptoms or crackling noises (Fig. 1). General Dentistry January/February 2015 e5 Surgical Orthodontics A large dentigerous cyst treated with decompression and orthosurgical traction: a case report Fig. 2. A panoramic radiograph of the 8-year-old patient at the initial visit showing a large radiolucency associated with the maxillary left canine and a supernumerary tooth. Fig. 4. Aspiration of yellowish liquid after punch biopsy. A panoramic radiograph revealed a radiolucent image at the maxillary left permanent canine and a supernumerary tooth, both of which were included (Fig. 2). To determine the limits of the lesion, a computed tomography (CT) scan was performed. The CT scan revealed a lesion with expansive root displacement of adjacent teeth (without signs of resorption) while preserving the left maxillary sinus floor (Fig. 3). Bone structure did not change. The muscles in the oral cavity had regular tomographic aspects and the subcutaneous tissue had no appreciable changes, suggesting an odontogenic cyst. Based on the clinical examination and imaging test results, an incisional biopsy was scheduled, preceded by a punch biopsy. The punch biopsy collected a yellowish liquid that contained suspended cholesterol crystals (Fig. 4). The decompression was performed and the cystic capsule fragments were collected. (Fig. 5-7). e6 January/February 2015 Fig. 3. A computed tomography scan (coronal slice) revealing the lesion with expansive root displacement of adjacent teeth. Fig. 5. Incision exposing the sealed cystic capsule. Fig. 6. The interior of the cyst after removal of the cystic capsule. Fig 7. The placement of furacin gauze pads and oral mucosa suture on the borders of the orifice. Fig. 8. Healed orifice before placement of a shutter. The collected material was submitted to histopathological analysis, which confirmed the diagnosis of odontogenic cyst. After 20 days, an acrylic shutter was placed to maintain an open surgical window, prevent the entrance of food, and facilitate cleaning by the patient (Fig. 8 and 9). At monthly follow-up visits, shutter reduction was performed, allowing for decompression as demonstrated by peripheral bone formation. This progressive reduction was performed to the point that the cavity was not deep enough to stabilize the General Dentistry www.agd.org Fig. 9. Acrylic shutter placed over the orifice to provide a surgical window. Fig. 10. Surgical removal of supernumerary tooth in palate. Fig. 11. Surgical exposure and orthodontic traction of left maxillary canine. A B C Fig. 12. Histological aspects of dentigerous cyst. Top. The fibrous cystic capsule exhibited numerous bundles of collagen fibers associated with small caliber vessels and small areas of bleeding (H&E, magnification 200X). Bottom. Fibrous connective tissue partially covered by non-keratinized stratified squamous epithelium with 2 or 3 layers of flattened cells and, in some cubic regions, with flat interface between epithelium and conjunctive tissue (H&E, magnification 100X). Fig. 13. Results 5 years and 2 months post-treatment. A. Panoramic radiograph showing the eruption of the left maxillary canine. B. Successful orthodontic traction of the maxillary left canine. C. Anterior photograph showing the erupted left maxillary canine. shutter. At that time, the surgery was scheduled for the enucleation of the remaining lesion. The patient subsequently underwent surgical removal of the supernumerary tooth and orthodontic treatment in order to facilitate the orthodontic traction of the maxillary left canine (Fig. 10 and 11). Microscopic examination of the histological sections revealed fibrous connective tissue covered partially by non-keratinized stratified squamous epithelium, with 2-3 layers of flattened cells and—in some cubic regions—a flat interface between the epithelium and conjunctive tissue. The fibrous cystic capsule in the tissues contained numerous bundles of collagen fibers associated with small caliber vessels and limited areas of bleeding (Fig. 12). Five years and two months posttreatment, no recurrence of the lesion www.agd.org was observed, and the preservation and positioning of the maxillary left canine (with the aid of orthosurgical traction) was successful (Fig. 13). Discussion Dentigerous cysts are associated with mandibular third molars, permanent canines, maxillary third molars, and second premolars; they also may be associated with supernumerary teeth.1 General Dentistry January/February 2015 e7 Surgical Orthodontics A large dentigerous cyst treated with decompression and orthosurgical traction: a case report Fenestration (a small opening of the cyst), marsupialization (a wide opening at the equator of the cyst), and decompression with shutters are different methods that all work on the same principle.4 The difference between decompression and marsupialization has been established in the literature. According to Tucker et al: Decompression and marsupialization, despite having the same function and sharing the same basic principle of bone regeneration, are two entirely different techniques. Although both of them have the purpose of relieving the pressure in the cystic cavity and allowing new bone formation, marsupialization is a one-stage surgery; decompression is a procedure of two stages.5 Marsupialization involves the opening of a window or surgical cavity on the cyst wall, allowing the emptying of its contents while maintaining the continuity between the cyst and the oral cavity. The maxillary sinus or the nasal cavity may also need emptying in cases of large cysts, impacted teeth associated with cysts in pediatric patients, or for patients with systemic diseases, such as the elderly.6 Decompression seeks the same results as marsupialization, but requires the placement of a device or intraoral drain tube. The tube allows for irrigation of the cystic cavity, helping to prevent food and microorganisms from accumulating in the area, which could lead to a secondary infection. This technique provides for the permeability of the cystic cavity, since the union of the cyst wall epithelium with the mucosa derives from the exteriorization of the injury. Another advantage lies in the fact that after the surgical procedure, the cyst capsule tends to become thicker, which would aid in either its complete removal or enucleation in a second surgical step.7,8 e8 January/February 2015 Decompression and marsupialization both reduce lesion size and induce bone formation, minimizing the extent of secondary surgery by means of mitigating pressure in the cystic cavity. It has also been observed that histological changes have been observed after both procedures, as the cystic epithelium is replaced eventually by oral epithelium.4 In the present case, decompression was the most appropriate treatment, due to the large size of the cystic lesion in the oral cavity. This technique made it possible to preserve the permanent canine, which helps to establish and maintain the form and function of the dentition. The canine’s presence in the dental arch is crucial for establishing balanced dynamic occlusion, esthetics, and facial harmony.9 In the treatment of impacted teeth, it is possible to preserve them through orthodontic planning; the treatment of choice is surgical exposure of the tooth and consequent orthodontic traction. However, after the extraction of primary teeth and cyst decompression, there is the possibility of spontaneous eruption without orthodontic intervention. The potential tooth eruption also depends on the stage of its rooting. An impacted tooth without complete root formation and an open apex has considerable eruption potential.10 In cases with small or large cystic lesions and a permanent included tooth, orthodontic evaluation and followup are necessary.6 Conclusion In cases involving large dentigerous cysts and the crown of a permanent tooth— where extraction is not indicated and the tooth is deemed necessary for physiological occlusion—a conservative treatment such as decompression, with or without orthodontic traction, may be the best treatment option. General Dentistry www.agd.org Author information Drs. Nascimento, Raldi, and de Moraes are professors, Department of Diagnosis and Surgery, Sao Jose dos Campos Dental School, Sao Paulo State University, Brazil, where Dr. Holleben is a dentist and an intern, Oral and Maxillofacial Surgery & Traumatology, and Dr. Cardoso is a professor, Department of Restorative Dentistry. References 1. Waldron CA. Cysts and odontogenic tumors. In: Neville BW, Damm DD, Allen CM, Bouquot JE, eds. Oral and Maxillofacial Pathology. 3rd ed. St. Louis: Elsevier Saunders; 2009:679. 2. Bastos EG, Cruz MC, Martins GA, Mendes MC, Marques RV. Marsupialization of mandibular dentigerous cyst in a 7-year-old child in the mixed dentition: case report [in Portuguese]. Rev Odontol UNESP. 2011; 40(5):268-271. 3. Berden J, Koch G, Ullbro C. Case series: treatment of large dentigerous cysts in children. Eur Arch Paediatr Dent. 2010;11(3):140-145. 4. Martorelli S, Coelho E Jr, Marinho E, Albuquerque R, Martorelli F, Machado de Andrade F. Keratocyst odontogenic tumor of the jaw: case report and management analysis. Int J Dent Recife. 2009;8(1):50-56. 5. Tucker WM, Pleasants JE, MacComb WS. Decompression and secondary enucleation of a mandibular cyst: report of case. J Oral Surg. 1972;30(9):669. 6. Berti S de A, Pompermayer AB, Couto Souza PH, Tanaka OM, Westphalen VP, Westphalen FH. Spontaneous eruption of a canine after marsupialization of an infected dentigerous cyst. Am J Orthod Dentofacial Orthop. 2010;137(5):690-693. 7.Giuliani M, Grossi BG, Lajolo C, Bisceglia M, Herb KE. Conservative management of a large odontogenic keratocyst: report of a case and review of the literature. J Oral Maxillofac Surg. 2006;64(2):308-316. 8. Maurette PE, Jorge J, Moraes M. Conservative treatment protocol of odontogenic keratocyst: a preliminary study. J Oral Maxillofac Surg. 2006;64(3):379-383. 9. Cappellette M, Cappellette M Jr, Fernandes LCM, de Oliveira AP, de Oliveira WC. Caninos permanentes retidos por palatino: diagnostico e terapeutica - uma sugesto tecnica de tratamento. Revista Dental Press de Ortodontia e Ortopedia Facial. 2008;13(1):60-73. 10. Hyomoto M, Kawakami M, Inoue M, Kirita T. Clinical conditions for eruption of maxillary canines and mandibular premolars associated with dentigerous cysts. Am J Orthod Dentofacial Orthop. 2003;124(5):515520. Dental Materials Impact of toothbrushing with a dentifrice containing calcium peroxide on enamel color and roughness Diala Aretha de Sousa Feitosa, DDS, MSc n Boniek Castillo Dutra Borges, PhD n Fabio Henrique de Sa Leitao Pinheiro, PhD Rosangela Marques Duarte, PhD n Renato Evangelista de Araujo, PhD n Rodivan Braz, PhD Maria do Carmo Moreira da Silva Santos, PhD n Marcos Antonio Japiassu Resende Montes, PhD the Ra increased in all groups after brushing, only the dentifrice containing calcium peroxide resulted in an increase in reflectance. Received: July 20, 2013 Accepted: November 12, 2013 This in vitro study sought to evaluate both the bleaching potential and changes to average surface roughness (Ra) of enamel after brushing with a dentifrice. Fifty-four enamel specimens (4 x 4 x 2 mm) were divided into 3 groups (n = 18) and treated with 1 of 3 dentifrices: 1 with calcium peroxide, and 2 without. The samples were submitted to 20,000 brushing cycles. Color and Ra were measured before and after brushing. Although M any patients consider an attractive smile to be synonymous with good health.1 The increased demand for enhanced esthetics has led to the development of bleaching products and whitening dentifrices.2 While bleaching peroxides cause decolorization (whitening) of the colored materials found within the tooth, whitening dentifrices are used to remove extrinsic stains with specific abrasives and/or chemical agents, such as hydrated silica, calcium pyrophosphate, and hydrogen or calcium peroxides.2,3 The high amounts of abrasives in dentifrices may increase enamel roughness and damage soft tissues and dental restorations, resulting in gingival recession, cervical Key words: dentifrice, tooth whitening, spectrophotometry, roughness abrasion, and dentinal hypersensitivity.1 It is expected that adding a chemical component (such as a peroxide) to a whitening dentifrice formulation would augment the abrasive cleaning by aiding in the removal and/or prevention of extrinsic stains.2 Presently there is a lack of research in the literature to confirm whether these whitening dentifrices have a greater impact on surface roughness compared to peroxidefree dentifrices. It has been demonstrated that calcium peroxide can release oxygen ions slowly and keep oxygen concentrations high.4 Bleaching is achieved, in part, from an oxireduction reaction in which reactive oxygen species attack the long-chained, Table 1. Dentifrices used in this study. Product Chemical composition Lot Colgate Total Advanced Clean Water, sorbitol, sodium lauryl sulphate, hydrated silica, methyl vinyl ether and maleic anhydride copolymer, carrageenan, flavor, sodium hydroxide, sodium fluoride, triclosan, sodium saccharin, titanium dioxide 0266BR121B Colgate Total Water, glycerin, hydrated silica, propylene glycol, sorbitol, Advanced Whitening sodium lauryl, carrageenan, cellulose gum, sodium saccharin, sodium fuoreto, triclosan, titanium dioxide, sodium hydroxide, CI 77891 (white) 0011BR123D Colgate Whitening Oxygen Bubbles 0051MX113E Water, glycerin, hydrated silica, sodium bicarbonate, propylene glycol, sodium triphosphate, carrageenan, tetrasodium pyrophosphate, cellulose gum, sodium saccharin, sodium monofluorophosphate, titanium dioxide, calcium peroxide, sodium hydroxide www.agd.org dark-colored chromophore molecules in dental tissues, breaking them down into smaller, lightly colored, and more diffusible molecules, thus this producing a whitening effect.5 In this sense, brushing teeth with calcium peroxide-containing whitening dentifrices might render the enamel prone to bleaching. This may or may not be associated with an increase in roughness, which varies according to the concentration of abrasives. To the best of the authors’ knowledge, this study is the first to evaluate the bleaching potential and surface roughness of enamel after brushing with a dentifrice that contains calcium peroxide. Two dentifrices that did not contain calcium peroxide served as controls. The null hypotheses tested were that there would be no differences in the bleaching potential among the products, and that none of the products would alter enamel surface roughness. Materials and methods Preparation of enamel samples This study was approved by the University of Pernambuco Ethics Committee under Protocol No. 194/10. Twenty-seven caries-free human third molars were stored for a maximum of 3 months in an aqueous 0.2% thymol solution. As confirmed by stereomicroscopic evaluation (magnification 25X), none of the selected teeth surfaces had cracks or abnormal anatomy. Using a water-cooled diamond saw (Isomet 1000, Buehler), a total of 54 enamel specimens (4 x 4 x 2 mm) were General Dentistry January/February 2015 e9 Dental Materials Impact of toothbrushing with a dentifrice containing calcium peroxide on enamel color and roughness Table 2. Reflectance means (SD) according to dentifrice and time. Table 3. Mean roughness values (SD) according to dentifrice and time of measurement. Dentifrice Before brushing After brushing Dentifrice Colgate Total Advanced Clean 0.673 (0.005) 0.667 (0.006) Colgate Total Advanced Whitening 0.672 (0.006) Aa Colgate Whitening Oxygen Bubbles 0.665 (0.007) Ba Aa Initial color and roughness assessment Using a computer-assisted spectrometer (with wavelengths ranging from 430 to 800 nm), color assessment was performed based on light reflectance. A halogen light (HL-2000-FSHA, Ocean Optics) and a fiberoptic cable (QR400-7-VIS-BX, Ocean Optics) with 6 optical fibers in a circular arrangement were used for light emission at a distance of 2 mm from the enamel slabs. Reflected light was collected by a centrally located optical fiber and transmitted to the spectrometer, which was connected to a computer. The wavelength-dependent light reflection intensity was calculated by using spectrometer operating software (SpectraSuite, Ocean Optics). Measurements were performed in a dark room with standardized air conditioning. A white standard plate (WS-1-SS, Ocean Optics) was used to calibrate the measurement unit. The specimens were attached to a holder so that the light would always be at the same place throughout repeated measurements (light focus diameter = 600 µm); the holder e10 January/February 2015 0.11 (0.01) 0.19 (0.04) Bb 0.669 (0.005) Ba Colgate Total Advanced Whitening 0.11 (0.01) Aa 0.25 (0.09) Ba 0.669 (0.004) Aa Colgate Whitening Oxygen Bubbles 0.10 (0.01) Aa 0.25 (0.13) Ba Different uppercase letters in rows and lowercase letters in columns indicate statistically significant differences ( P < 0.05). also served as an integrating sphere that maximized the collection of diffused light inside the sphere. Reflectance was equalized arbitrarily at a wavelength of 600 nm (reflectance = 1:600 nm), indicating that numerical values represented arbitrary units rather than absolute reflectance. Test samples were measured 4 times. Surface roughness tests were performed with a roughness tester (Surftest SL-201, Mitutoyo America Corporation). Three measurements were taken at the center of each specimen in different directions. The cut-off surface roughness value was 0.25 mm and the sampling length for each measurement was 0.75 mm. The average surface roughness (Ra) value was obtained for each specimen. Toothbrush test Three dentifrices were tested in this study. One contained calcium peroxide (Colgate Whitening Oxygen Bubbles, ColgatePalmolive Company), while the other 2, Colgate Total Advanced Clean (ColgatePalmolive Company) and Colgate Total Advanced Whitening (Colgate-Palmolive Company), were used as controls (Table 1). After roughness and color assessments, the specimens were brushed using a mechanical device equipped with 10 soft bristle toothbrush heads (ColgatePalmolive Company) containing dentifrice slurry. The machine was set to brush at a rate of 60 reciprocal strokes per minute and to generate a vertical load of 200 g against the specimens. The specimens were submerged statically during brushing by inserting 150 ml of dentifrice slurry (100 ml of deionized water and 50 g of General Dentistry After brushing Colgate Total Advanced Clean Different uppercase letters in rows and lowercase letters in columns indicate statistically significant differences ( P < 0.05). prepared from the labial to lingual aspects. The enamel samples were embedded in a chemically cured resin, leaving the exposed buccal surface to be smoothed by a polishing machine (LaboPol-21, Struers, Inc.). Aluminum oxide disks were used in sequential grit sizes of 400, 600, and 1200. A final polishing was accomplished with a felt cloth containing a diamond paste in a polishing machine (Ecomet 3, Buehler). These procedures were performed to obtain homogeneous surfaces for treatment. Before brushing Aa Ba www.agd.org dentifrice) into the slurry bath. The total brushing time was 10 hours, the equivalent of 20,000 cycles.6 Every 200 double strokes was accompanied by 20 ml of renewed slurry dispensed into the slurry bath. The toothbrushes were replaced after 10,000 double strokes. The samples were rinsed with deionized water and cleaned ultrasonically for 10 minutes before recording mean reflectance and Ra values, as described previously. Statistical analysis Descriptive statistics data—including means and standard deviation—were calculated for each experimental group. One-way ANOVA with repeated measurements and Tukey multicomparison tests were used to compare the mean reflectance and Ra values between the groups. The significance level for all statistical tests was set at 5%. All data were entered and analyzed by SAS software 9.1 for Windows (SAS Institute, Inc.). Results Color The mean reflectance values are listed in Table 2. Statistically similar values were found between dentifrices either before or after brushing. However, only Colgate Whitening Oxygen Bubbles provided increased reflectance values after brushing. The control dentifrices saw a decrease in enamel reflectance. Roughness All the Ra values are listed in Table 3. The samples presented similar Ra values before brushing. All tested dentifrices produced increased Ra values, with Colgate Total Advanced Whitening and Colgate Whitening Oxygen Bubbles yielding the highest Ra mean values. Discussion Based on the findings of this study, both null hypotheses were rejected. Although each dentifrice tested showed increased enamel Ra values after brushing, the dentifrice containing calcium peroxide demonstrated some bleaching potential. Currently, tooth color is measured using a wide range of measurement methods, divided into subjective (visual) and objective (instrumental) assessments.7 Instrumental measurement devices—such as reflectance spectrophotometers, colorimeters, and digital image analysis systems (including quantitative light-induced fluorescence)— are supplementary adjuncts to visual evaluation of tooth color. The primary difference is that spectrophotometers measure the reflectance of light within the entire visible spectrum, whereas colorimeters only evaluate the reflected light through 3 wavelengths: red, green, and blue.8 In addition, reflectance spectrophotometry has given reproducible results when measuring small changes in tooth color.9 Since the samples treated with the dentifrice containing calcium peroxide demonstrated statistically higher reflectance values, it is likely that this whitening dentifrice was the only one in the present study capable of bleaching teeth. As stated previously, calcium peroxide released oxygen ions slowly, thus maintaining high levels of oxygen inside the teeth, which is capable of breaking long-chained, dark-colored chromophore molecules into smaller, lightly colored, and more diffusible molecules.4 This transition is necessary to provide the tooth with a “brightened” appearance.5 External factors such as surface morphology can affect the amount and type of reflection. The rough surface of the enamel after brushing results in a diffuse scattered reflection. All dentifrices have varying degrees of enamel roughness. All 3 of the dentifrices used in the present study contained abrasives that could have promoted alterations in enamel. However, there was no decrease in reflectance after brushing with the dentifrice containing calcium peroxide (Colgate Oxygen Bubbles). In this sense, it is reasonable to assume that calcium peroxide might have provided the enamel with a clear color (resulting in increased light reflectance), regardless of surface roughness. Also, the fact that the dentifrice containing the chemical agent calcium peroxide promoted the highest Ra values indicates that this agent worked in association with the abrasive found in the dentifrice. However, further studies should investigate if saliva could revert roughness alterations without compromising the bleaching potential of dentifrices containing calcium peroxide. Conclusion Although all 3 dentifrices changed the surface roughness of the enamel samples in this in vitro study, only the dentifrice containing calcium peroxide showed increased reflectance values. Author information Dr. Feitosa is a doctoral candidate, Department of Restorative Dentistry, Pernambuco School of Dentistry, University of Pernambuco, Camaragibe, Brazil, where Drs. Braz, Santos, and Montes are associate professors. Dr. Araujo is an associate professor, Department of Biomedical Sciences, Federal University of Pernambuco, Recife, Brazil. Dr. Borges is an associate professor, Department of Dentistry, Federal University of Rio Grande do Norte, Natal, Brazil. Dr. Pinheiro is an assistant professor, Division of Orthodontics, University of Manitoba, Winnipeg, Canada. Dr. Duarte is an associate professor, Department of Restorative Dentistry, Federal University of Paraíba, Joao Pessoa, Brazil. www.agd.org Acknowledgments This study was supported by the Brazilian Federal Agency for the Support and Evaluation of Graduate Education (CAPES) and the National Institute of Science and Technology Photonics (INCT Fotonica CNPq), Brazil. Disclaimer The authors have no financial, economic, commercial, and/or professional interests related to topics presented in this article. References 1. Joiner A, Pickles MJ, Lynch S, Cox TF. The measurement of enamel wear by four toothpastes. Int Dent J. 2008; 58(1):23-28. 2. Joiner A. Whitening toothpastes: a review of the literature. J Dent. 2010;38(Suppl 2):e7-e24. 3. Joiner A. The bleaching of teeth: a review of the literature. J Dent. 2006;34(7):412-419. 4. Huang JJ, Li YH, Sun JM, Li N. Municipal river sediment remediation with calcium nitrate, polyaluminium chloride and calcium peroxide compound. Adv Mat Res. 2012;396-398:1899-1904. 5. Plotino G, Buono L, Grande NM, Pameijer CH, Somma F. Nonvital tooth bleaching: a review of the literature and clinical procedures. J Endod. 2008;34(4):394-407. 6. Belli R, Rahiotis C, Schubert EW, Baratieri LN, Petschelt A, Lohbauer U. Wear and morphology of infiltrated white spot lesions. J Dent. 2011;39(5):376-385. 7. Brook AH, Smith RN, Lath DJ. The clinical measurement of tooth colour and stain. Int Dent J. 2007;57(5): 324-330. 8. Karamouzos A, Papadopoulos MA, Kolokithas G, Athanasiou AE. Precision of in vivo spectrophotometric colour evaluation of natural teeth. J Oral Rehabil. 2007; 34(8):613-621. 9. Lenhard M. Assessing tooth colour change after repeated bleaching in vitro with a 10 percent carbamide peroxide gel. J Aust Dent Soc. 1996;127(11):16181624. Manufacturers Buehler, Lake Bluff, IL 800.283.4537, www.buehler.com Colgate-Palmolive Company, New York, NY 800.226.4283, colgate.com Mitutoyo America Corporation, Elk Grove Village, IL 888.648.8869, www.mitutoyo.com Ocean Optics, Dundein, FL 727.733.2447, oceanoptics.com SAS Institute, Inc., Cary, NC 800.727.0025, www.sas.com Struers, Inc., Westerville, OH 440.871.0071, www.struers.com General Dentistry January/February 2015 e11 Obturation Techniques Apical plug technique in a calcified immature tooth: a case report Kumar Raghav Gujjar, MDS n Ratika Sharma, MDS n Amith H.V., MDS n Smitha Amith, MDS n Indushekar K.R., MDS Traumatic injury to an immature tooth may result in pulpal necrosis secondary to pulp canal obliteration, which makes the management of the tooth a clinical challenge for dentists. The present case report describes an innovative apical plug technique with mineral trioxide aggregate in a calcified immature tooth using an ultrasonic tip and long, thin, tapered E pidemiological studies show that 11.6%-33.0% of boys and 3.6%19.3% of girls suffer dental trauma of varying severity before the age of 12 years.1-3 Studies indicate that approximately 3.8%-24.0% of traumatized teeth can develop varying degrees of pulp space obliteration, which develops into pulpal necrosis in 1%-16% of reported cases.4 Calcific obliteration of the pulp canal space may happen after a severe traumatic injury to immature permanent teeth.5 In such a scenario, the pulp becomes necrotic, leading to the formation of a periapical lesion around a wide-open apex. These conditions present the following endodontic challenges to a dentist: a partial or complete obliteration of the pulp canal space, causing difficulty in accomplishing root canal treatment; or a periapical lesion with an open apex, potentially preventing a hermetic apical seal with conventional root canal treatment.6 Treatment options in such a situation are either extraction or apicoectomy. There is little research found in the literature on the management of symptomatic young permanent teeth with calcific metamorphosis. The present case report describes a novel technique of gaining access through the calcified root canal in a nonvital young permanent upper central incisor followed by apical plugging with mineral trioxide aggregate (MTA). Case report A 10-year-old boy reported to the Department of Pediatric Dentistry, Seema Dental College, Rishikesh, India, with severe pain and swelling in the upper front region of the jaw which had persisted for 2 days. The pain, which preceded the e12 January/February 2015 fissure burs. The technique was proven to be successful clinically and radiographically at 2 years postobturation. Received: June 19, 2013 Accepted: September 25, 2013 swelling, was continuous and severe with resultant sleep disturbance. The swelling had appeared a day after the onset of pain. The patient’s medical history was noncontributory; however, his dental history revealed trauma in the upper front region of the jaw 6 months prior via a contact sports incident. The child had reported to a general dentist with a broken coronal tooth fragment and no evidence of any displacement. Since there was no pulp exposure, the dentist reattached the fractured coronal tooth fragment and the procedure was uneventful. After 6 months, the child reported to the dentist again with pain and swelling, and an unsuccessful attempt was made to drain the abscess through the root canal. The child was then referred to the Department of Pediatric Dentistry. The patient was febrile, and intraoral examination showed obliteration of the upper labial vestibule on the right side. The permanent upper right central incisor was extremely tender to touch and slightly labially proclined. It showed a yellowish discoloration in the reattached coronal fracture fragment. The rest of the dentition was deemed healthy. An intraoral periapical radiograph of the permanent upper right central incisor region revealed the reattached coronal fracture fragment, an attempted endodontic access cavity preparation, loss of lamina dura at the periapical region, an open apex, and calcific obliteration of the coronal pulp chamber and the cervical and middle thirds of the radicular pulp chamber (Fig. 1). The tooth did not respond to sensitivity tests. Clinical and radiographic examination indicated acute periapical abscess in the permanent upper right central incisor. General Dentistry www.agd.org A decision was made to facilitate drainage of the abscess in the maxillary upper right central incisor through the root canal, followed by apical plugging with MTA. An informed consent for the treatment procedure was obtained from the parents with due warning of the risks involved, especially the risk of perforation while gaining access to the root canal. Following anesthesia, access to the apical third of the root canal was established using gentle brushing strokes with thin, long, tapered fissure burs (Mani, Inc.) and a long thin ultrasonic tip (Satelec-ET20 tip, Acteon North America) in a direction parallel to the long axis of the tooth at the crosssectional midpoint of the root canal to prevent perforation. A Glyde File Prep (DENTSPLY Maillefer) was used intermittently between instrumentation as a chelating agent. Penetration was continued using an endodontic explorer to locate the orifice. A No. 8 file was used in an attempt to negotiate the canal. Access to the apical third of the root canal was successfully established. A radiograph was obtained and the estimated working length was established as 24.5 mm. The canal was sequentially widened by a Hedstrom file to size 30, and the abscess was drained through the root canal. The access cavity was sealed with a cotton dressing. The authors found this cautious technique useful as it minimized the risk of perforation. The child was prescribed a course of amoxicillin capsules 250 mg tid for 5 days, metronidazole tablets 200 mg tid for 5 days, and ibuprofen 200 mg/paracetomol tablets 125 mg tid for 3 days. Fig. 1. Preoperative radiograph of the permanent upper right central incisor. Fig. 2. Radiograph of permanent upper right central incisor after obturation. The patient was assessed every 24 hours, and the canal cleansed with endodontic files so as to facilitate drainage. After 72 hrs, the canal of the asymptomatic tooth was sequentially widened with a size 60 file, and filled with Metapex (META-BIOMED US Corporation) as an intracanal medicament. Two weeks later, the tooth was irrigated with saline and the Glyde File Prep was used to remove any remnants of Metapex and the smear layer. After drying the canal, white MTA powder (DENTSPLY Tulsa Dental Specialties) was mixed with the provided water ampule per the manufacturer’s instructions. The mix was then placed in the canal with an amalgam carrier and packed to form an apical plug of approximately 5 mm. A moist cotton pellet was placed over the apical plug and the access cavity was sealed. The next day, the cotton pellet was removed and the canal thoroughly dried with absorbent points. An endodontic plugger was used to check the consistency of the MTA and to ensure it had completely set. Subsequently, a backfill was performed using gutta percha (DENTSPLY Maillefer) by cold compaction method. A postobturation radiograph confirmed the completion of endodontic therapy (Fig. 2). Figure 3 shows the success of the treatment at 2 years postobturation. Discussion Fig. 3. Radiograph of permanent upper right central incisor showing evidence of healing in the periapical region 2 years postobturation. Fischer first indicated in 1974 that calcific metamorphosis (CM) was a response to trauma presenting progressive hard tissue formation with maintenance of vital tissue and a pulp space observed up to the apical foramen.7 Fischer argued that such cases require root canal treatment because of reduced cellular content leading to decreased ability for healing, thereby predisposing the pulpal tissue to infection. The mechanism of hard tissue formation during CM is not yet clear, although several hypotheses have been proposed to explain this phenomenon. Torneck hypothesized that the deposition of hard tissue was either a result of stimulation of the preexisting odontoblasts or by loss of their regulatory mechanisms.8 Andreasen & Andreasen described CM as a response to a severe injury to the neurovascular supply of the pulp, which after healing, leads to accelerated dentin deposition, which in turn is closely related to the loss and reestablishment of the pulpal neural supply.9 Ten Cate identified this process as the deposition of tertiary or reparative dentin in response to irritation or trauma.10 Reparative odontoblasts are somehow able to differentiate from dental pulp cells in the absence of any epithelial influence.10 Subodontoblast www.agd.org cells under certain influences differentiate into odontoblast-like cells and deposit dentin-like hard tissue.10 Reparative dentin or tertiary dentin is deposited at specific sites in response to injury, and the rate of deposition depends on the degree of injury.10 With an increase in severity of injury, there is a rapid rate of dentin deposition, possibly as much as 3.5 mm/day.10 The accelerated hard tissue formation traps some pulpal cells and gives the histological appearance of osteodentin with an irregular tubular pattern. Evidence indicates that reparative dentin is produced by odontoblast-like cells and incorporates type I and III collagen in its matrix, which exhibits diminished phosphophoryn content.10 Neither of the above mechanisms described has been proven, therefore further investigation is required to provide an evidencebased understanding of this occurrence. In the treatment of calcified canals, a total occlusion at any level of the canal space is a common finding.11 Smith performed a literature review and found that teeth with calcific metamorphosis had a 0%-16% incidence of periapical pathosis development.12 Teeth with CM fall into the high difficulty category of the Endodontic Case Difficulty Assessment proposed by the American Association of Endodontists, and General Dentistry January/February 2015 e13 Obturation Techniques Apical plug technique in a calcified immature tooth: a case report it has been suggested that achieving a predictable outcome will be challenging for even experienced practitioners.13 The obliteration of the root canal complicates endodontic treatment of a symptomatic nonvital tooth. Traditionally, the treatment in such cases involves either extraction or apicoectomy. An early loss of teeth, particularly in the anterior region of the maxilla, is associated with numerous problems. Poor esthetics, psychological trauma, phonetic problems, and malocclusion are potential consequences. The possibilities of prosthetic restoration during childhood are restricted. Apicoectomy involves a surgical retrograde approach to access the apical portion of the tooth. Along with the obvious risks of the surgical procedure, there is a concomitant reduction in the crown to root ratio, potentially causing psychological trauma if performed at an early age, along with the inability to obtain an appropriate apical seal if performed in young permanent teeth. Therefore, choosing an orthograde technique in such cases may prove to be a better option. In the past, the treatment of choice in an immature tooth with an open apex was to achieve an apical closure by the apexification technique using long-term calcium hydroxide dressings. Successful apexification depends on the formation of a hard tissue barrier by cells that migrate from the periradicular tissues to the apex and differentiate under the influence of specific cellular signals to cells capable of secreting an organic matrix consisting of cementum or osteodentine.14 However, the placement of calcium hydroxide has potential disadvantages, including the variability of treatment time (3-21 months), unpredictability of apical closure, difficulty in patient follow-up, and delayed treatment.15,16 The duration depends on factors such as the diameters of the open apices, the degree of tooth displacement by trauma, and the method used for tooth repositioning. During the apexification procedure, the root canal is susceptible to reinfection because of the temporary coronal seal. The affected tooth is also susceptible to fracture.17 Rosenberg et al investigated the effect of calcium hydroxide on the microtensile fracture strength of extracted human permanent maxillary incisors and reported severe decreases in the dentine fracture strength (23.0%-43.9%).18 e14 January/February 2015 An alternative for the multi-appointment apexification procedure is a single-step technique by means of an apical barrier. Several materials, such as tricalcium phosphate, calcium hydroxide, collagen calcium phosphate, osteogenic protein-1, bone growth factor, and MTA have been proposed for use as apical barriers, and their biocompatibility and osteogenic potential have been demonstrated.19-21 In 1999, Torabinejad & Chivian introduced the use of MTA as an apical plug.22 The final setting time of MTA is approximately 3 hours; the pH directly after mixing is 12.5.23 The main compounds of MTA are tricalcium silicate, tricalcium aluminate, tricalcium oxide, silicate oxide, and other mineral oxides; bismuth oxide is also added to increase the radiopacity of the compound.24 MTA shows good sealing ability, good marginal adaptation, a reasonable setting time, and a high degree of biocompatibility.16 The 2 important contributors for the favorable biologic response stimulated by MTA in human periapical tissues are bone morphogenetic protein-2 and transforming growth factor β1.25 The stimulation of interleukin production by MTA may allow for the overgrowth of cementum and facilitate the regeneration of the periodontal ligament and formation of bone.26 In the present case, advanced osseous healing of the periapical lesions was evident as early as 6 months after placement of the MTA apical plug. Contemporary data suggest that MTA can be successfully used as an apical barrier in teeth with necrotic pulps and open apexes. Additional investigations are needed to prove its long-term efficacy.16 This case confirmed that MTA acts as an apical barrier and can be considered a very effective material to support regeneration of the periapical tissue in a young permanent tooth with an infected root canal. Clinical and radiographic follow-ups showed healing of the apical area of the affected tooth. The main advantage of the single-step procedure for the treatment of pulpless teeth with immature roots is the high predictability of apical closure and the reduction of treatment time, number of appointments, and radiographs. General Dentistry www.agd.org The inherent disadvantage of both the traditional apexification with calcium hydroxide and the artificial apical barrier with MTA is that neither technique allows for further root development in terms of thickening of the root canal walls or continued root formation. Recently, new promising concepts aimed at revascularisation of the necrotic pulp of such teeth have been advocated.27-29 Revascularization has been considered a better option for dealing with an immature tooth with a nonvital pulp—even in cases with severe periapical infection.28,30 This alternative method seems to have the potential for increasing the root length and thickness of root canal walls of nonvital immature teeth, assisted by blood clotting and a collagen-enhanced matrix. From this perspective, it has been recently proposed that apexification may not be needed in the near future.29 Nevertheless, controlled clinical studies to demonstrate that the revascularization method can replace established treatment protocols based on calcium hydroxide or MTA are warranted. Summary Approximately 3.8%-24.0% of traumatized teeth develop varying degrees of calcific metamorphosis. Although there are different opinions on the management of pulps exhibiting canal obliteration, studies indicate that the incidence of pulpal necrosis in these teeth is between 1% and 16%. Endodontic treatment of a symptomatic nonvital young permanent tooth with a calcified canal is a clinical challenge to dentists who work with pediatric patients. The authors found that the cautious technique that was used to gain access through the calcified canal was valuable in this case, as it minimized the risk of perforation. This technique also confirmed that MTA acts as an apical barrier and can be considered a very effective material to support regeneration of the periapical tissue in a tooth with an infected root canal and an open apex. Sound knowledge of tooth morphology, coupled with meticulous technique and patience, are the secrets of success in this type of situation. The meticulous orthograde technique employed in the present case in gaining access through the calcified canal of a young permanent tooth could be of immense benefit to any dentist who works with pediatric patients. Author information Dr. Gujjar is a senior lecturer, Pediatric Dentistry, Faculty of Dentistry SEGi University, Malaysia. Dr. Sharma is a senior lecturer, Department of Public Health Dentistry, M.N.R Dental College, Hyderabad, India. Dr. Amith H.V. is a reader/associate professor, Department of Community Dentistry, People’s College of Dental Sciences, Bhopal, Madhya Pradesh, India, where Dr. S. Amith is a postgraduate trainee in Oral & Maxillofacial Pathology, Department of Oral & Maxillofacial Pathology. Dr. Indushekar is the director of Postgraduate Studies, and department head, Pedodontics & Preventive Dentistry, Sudha Rustagi College of Dental Sciences & Research, Faridabad, Haryana, India. References 1. Clarkson BH, Longhurst P, Sheiham A. The prevalence of injured anterior teeth in English school children and adults. J Dent Child. 1973;4(1):21-24. 2. Jarvinen S. Fractured and avulsed permanent incisors in Finnish children. A retrospective study. Acta Odontol Scand. 1979;37(1):47-50. 3. Baghdady VS, Ghose LJ, Enke H. Traumatized anterior teeth in Iraqi and Sudanese children—a comparative study. J Dent Res. 1981;60(3):677-680. 4. Amir FA, Gutmann JL, Witherspoon DE. Calcific metamorphosis: a challenge in endodontic diagnosis and treatment. Quintessence Int. 2001;32(6):447-455. 5. Heling I, Slutzky-Goldberg I, Lustmann J, Ehrlich Y, Becker A. Bone-like tissue growth in the root canal of immature permanent teeth after traumatic injuries. Endod Dent Traumatol. 2000;16(6):298-303. 6. Ngeow WC, Thong YL. Gaining access through a calcified pulp chamber: a clinical challenge. Int Endod J. 1998;31(5):367-371. 7. Fischer C. Hard tissue formation of the pulp in relation to treatment of traumatic injuries. Int Dent J. 1974; 24(3):387-396. 8. Torneck C. The clinical significance and management of calcific pulp obliteration. Alpha Omegan. 1990; 83(4):50-54. 9. Andreasen J, Andreasen F. Textbook and Color Atlas of Traumatic Injuries to Teeth. 3rd ed. Copenhagen: Munksgaard; 1994. 10. Ten Cate AR. Oral Histology: Development, Structure, and Function. 5th ed. St Louis: Mosby; 1998. 11. Gutmann J.L, Dumsha T.C, Lovdahl P.E, Hovland E.J. Problem Solving in Endodontics: Prevention, Identification and Management. 3rd ed. St. Louis: Mosby; 1997. 12. Smith JW. Calcific metamorphosis: a treatment dilemma. Oral Surg Oral Med Oral Pathol. 1982;54(4): 441-444. 13. American Association of Endodontics. AAE Endodontic Case Difficulty Assessment Form and Guidelines. Available at: http://www.aae.org/uploadedfiles/dental_ professionals/endodontic_case_assessment/2006case difficultyassessmentformb_edited2010.pdf. Accessed October 9, 2014. 14. Ripamonti U, Reddi AH. Tissue engineering, morphogenesis, and regeneration of the periodontal tissues by bone morphogenetic proteins. Crit Rev Oral Biol Med. 1997;8(2):154-163. 15. Metzger Z, Solomonov M, Mass E. Calcium hydroxide retention in wide root canals with flaring apices. Dent Traumatol. 2001;17(2):86-92. 16. Giuliani V, Baccetti T, Pace R, Pagavino G. The use of MTA in teeth with necrotic pulps and open apices. Dent Traumatol. 2002;18(4):217-221. 17. Andreasen JO, Farik B, Munksgaard EC. Long-term calcium hydroxide as a root canal dressing may increase risk of root fracture. Dent Traumatol. 2002;18(3):134-137. 18. Rosenberg B, Murray PE, Namerow K. The effect of calcium hydroxide filling on dentine fracture strength. Dent Traumatol. 2007;23(1):26-29. 19. Roberts SC Jr, Brilliant JD. Tricalcium phosphate as an adjunct to apical closure in pulpless permanent teeth. J Endod. 1975;1(8):263-269. 20. Michanowicz JP, Michanowicz AE. A conservative approach and procedure to fill an incompletely formed root using calcium hydroxide as an adjunct. J Dent Child. 1967;34(1):42-47. www.agd.org 21. Nevins A, Finkelstein F, Laporta R, Borden BG. Induction of hard tissue into pulpless open-apex teeth using collagen-calcium phosphate gel. J Endod. 1978;4(3): 76-81. 22. Torabinejad M, Chivian N. Clinical applications of mineral trioxide aggregate. J Endod. 1999;25(3):197-205. 23. Torabinejad M, Hong CU, McDonald F, Pitt Ford TR. Physical and chemical properties of a new root-end filling material. J Endod. 1995;21(7):349-353. 24. Camilleri J, Montesin FE, Brady K, Sweeney R, Curtis RV, Ford TR. The constitution of mineral trioxide aggregate. Dent Mater. 2005;21(4):297-303. 25. Guven G, Cehreli ZC, Ural A, Serdar MA, Basak F. Effect of mineral trioxide aggregate cements on transforming growth factor beta1 and bone morphogenetic protein production by human fibroblasts in vitro. J Endod. 2007;33(4):447-450. 26. Al-Rabeah E, Perinpanayagam H, MacFarland D. Human alveolar bone cells interact with ProRoot and tooth-colored MTA. J Endod. 2006;32(9):872-875. 27. Banchs F, Trope M. Revascularization of immature permanent teeth with apical periodontitis: new treatment protocol? J Endod. 2004;30(4):196-200. 28. Hargreaves KM, Geisler T, Henry M, Wang Y. Regeneration potential of the young permanent tooth: what does the future hold? Pediatr Dent. 2008;30(3):253-260. 29. Huang GT. Apexification: the beginning of its end. Int Endod J. 2009;42(10):855-866. 30. Huang GT. A paradigm shift in endodontic management of immature teeth: conservation of stem cells for regeneration. J Dent. 2008;36(6):379-386. Manufacturers Acteon North America, Mount Laurel, NJ 800.289.6367, www.acteonsupport.com DENTSPLY Maillefer, Tulsa, OK 800.924.7393, www.maillefer.com DENTSPLY Tulsa Dental Specialties, Tulsa, OK 800.662.1202, www.tulsadentalspecialties.com Mani, Inc., Toshigi, Japan 81.028.667.1811, www.mani.co.jp/en META-BIOMED US Corporation, Horsham, PA 267.282.5893, www,meta-biomed.com General Dentistry January/February 2015 e15 Diagnosis and Treatment Planning Central giant cell lesion: diagnosis to rehabilitation Ana Carolina Amorim Pellicioli, DDS n Thieni Kaefer, DDS n Marco Antonio Trevizani Martins, DDS, PhD Vinicius Coelho Carrard, DDS, PhD n Manoela Domingues Martins, DDS, PhD Central giant cell lesion (CGCL) is a benign bone lesion of unknown etiology that primarily affects the mandible, with a predilection for female children and young adults. This article describes a case of a 16-year-old boy with a palatal swelling of approximately 18 months duration. Clinical, radiographic, histopathological, and hematological examinations led to a diagnosis of CGCL. Treatment involved a complete enucleation of the lesion and the removal of several teeth. A subsequent esthetic/functional C entral giant cell lesion (CGCL) is a benign bone lesion of unknown etiology.1,2 It was first described by Jeffe in 1953.3,4 This lesion mainly affects children and young adults (<30 years of age), with a predilection for the female gender.1-4 The mandible is the most common site for CGCL, which accounts for <7% of all benign lesions in gnathic bones.5 CGCL exhibits varying clinical behavior. Some lesions are asymptomatic and demonstrate slow growth, whereas more aggressive forms show rapid growth and can cause pain, root resorption, tooth mobility, perforation of the bone cortex, and paresthesia.6,7 Histologically, CGCL consists of a proliferation of fusiform cells in a collagenized stroma interwoven with multinucleated giant cells.3 Since other conditions (such as cherubism and brown tumor of hyperparathyroidism) can resemble CGCL histologically and radiographically, CGCL is diagnosed through a combination of clinical, histological, radiographic, and hematological examinations.3,5 rehabilitation was performed using a removable prosthesis. The patient was submitted to rigorous clinical and radiographic follow-ups, with no signs of recurrence over a 7-year period. Received: October 8, 2012 Accepted: March 4, 2013 Key words: central giant cell lesion, oral rehabilitation, proliferative lesion Treatment options range from nonsurgical options to curettage and en bloc resection.8 The latter is the treatment of choice for more aggressive cases, due to the high rate of recurrence (13%-49%).9 Nonsurgical treatment options include calcitonin injections, intralesion injections of corticosteroids, and subcutaneous injections of α-interferon.1,10,11 This article describes the case of a CGCL in the jaw of a 16-year-old boy and discusses the histopathological, clinical, radiological, and therapeutic features as seen in the literature. Patient management after lesion removal (including prosthetic rehabilitation) is discussed also. No. 12-15 (Fig. 1). A pulp vitality test was positive for all the teeth in question. Panoramic, occlusal, and periapical radiographic examinations revealed a well-defined, unilocular radiolucent image at the periapex of teeth No. 12-15, measuring 4 x 3 cm at its largest diameter (Fig. 2). Computed tomography of the patient’s face revealed an expansive lesion in the right maxilla causing bone destruction of the nasal fossa, maxillary sinus, and outer bone cortex (Fig. 3). Case report A 16-year-old boy sought treatment for swelling in the roof of his mouth. The swelling had started approximately 18 months earlier, and the patient reported no pain. An intraoral examination revealed an expansive growth in the maxilla covered by intact mucosa (with elastic consistency upon palpation) and mobility of teeth Fig. 1. Photograph showing anterior view of a central giant cell lesion (CGCL) with expansive growth in the maxilla of a 16-year-old boy. Fig. 2. Radiographs revealing a well-defined, unilocular radiolucent image in the right maxilla. Left. Panoramic view. Center. Occlusal view. Right. Periapical view. e16 January/February 2015 General Dentistry www.agd.org Fig. 3. Computed tomography showing an expansive lesion that is destroying adjacent bone structures. Left. Coronal view. Right. Facial view. Fig. 5. Photograph of teeth No. 12-15 postextraction. The clinical and imaging examinations led to the differential diagnoses of ameloblastoma, keratocystic odontogenic tumor, or CGCL. Calcium and phosphorus levels were normal, which eliminated the diagnosis of hyperparathyroidism. An incisional biopsy was performed and the material was sent for histopathological analysis. This analysis revealed a proliferation of fusiform cells with a voluminous nucleus in a collagenized stroma interwoven with multinucleated giant cells and sites of hemorrhage. The histopatholological diagnosis was CGCL (Fig. 4). Treatment consisted of the complete enucleation of the lesion under general anesthesia, for which it was necessary to remove teeth No. 12-15 (Fig. 5-7). Initially, a temporary removable partial denture (RPD) was made of a flexible material; later, a permanent metallic RPD was used for esthetic/functional rehabilitation (Fig. 8 and 9). The patient underwent a rigorous clinical and radiographic followup period of 7 years, during which no signs of recurrence were noted (Fig. 10). Fig. 4. Histopathology slide revealing a proliferation of fusiform cells in a collagenized stroma interwoven with multinucleated giant cells (H&E, magnification 400X). Fig. 6. Anterior radiograph of the patient after the extraction of teeth No. 12-15. Fig. 7. Anterior photograph showing where the teeth were extracted. Fig. 8. The removable partial denture (RPD) used for patient esthetic/functional rehabilitation. Fig. 9. Photograph of patient’s smile with the RPD. Fig. 10. A panoramic radiograph taken 7 years post-treatment showing no signs of recurrence. www.agd.org General Dentistry January/February 2015 e17 Diagnosis and Treatment Planning Central giant cell lesion: diagnosis to rehabilitation Discussion The World Health Organization recently defined CGCL as a localized benign lesion (manifesting at times as an aggressive proliferative osteolytic lesion) that is formed by fibrous conjunctive tissue containing multinucleated giant cells, hemorrhage and hemosiderin deposits, and areas of bone formation.12 The etiopathogenesis of CGCL is not yet well-established; however, it has been suggested that the lesion develops due to an exacerbated repair process following trauma or hemorrhage.13,14 CGCL is a benign lesion that is divided clinically and radiographically into 2 subtypes: aggressive and nonaggressive.4,9 The aggressive type is more common among young patients; it exhibits fast growth, perforation of the bone cortex, root resorption, pain, and a tendency toward recurrence.4,9 The nonaggressive type generally is asymptomatic, exhibiting slow growth with no bone or root resorption and a low incidence of recurrence.4,9 It has been suggested that larger lesions with a greater area of multinucleated giant cells are more aggressive.15,16 The present case involved an expansive lesion with slow growth (>1 year) and well-defined edges. These symptoms suggest the lesion was nonaggressive, which was indicated by the lack of recurrence over the 7-year follow-up period. A conclusive diagnosis of CGCL requires a combination of clinical, radiographic, and histological examinations.3 The histopathological aspects of 2 other conditions (cherubism and brown tumor of hyperparathyroidism) are identical to those of CGCL.17 To discard the possibility of parathyroid abnormalities, which require different therapeutic management, cases of suspected CGCL should be submitted to hematological examinations so that calcium, alkaline phosphatase, phosphorus, and parathyroid hormone levels may be assessed.1,4 For cases involving the mandible, it is necessary to determine whether the lesion is singular or bilateral, as cherubism is characterized in young patients by osteolytic lesions on both sides of the mandible.18 Whitaker & Waldron reported a mean interval of 21 months between treatment and recurrence, with rare cases of recurrence more than 2 years following initial treatment.19 The main factors associated with recurrence are clinical lesion e18 January/February 2015 activity (72% of aggressive lesions recur, whereas only 3% of nonaggressive lesions recur), patient age, perforation of the bone cortex, and tumor size.20-22 In the present case, the patient showed no signs of recurrence during a 7-year follow-up period that involved rigorous clinical and radiographic examinations. A number of therapies for treating CGCL— including the intralesion injection of corticosteroids and calcitonin— have been studied as ways to complement or reduce the extent of surgical resection.1 Calcitonin use is based on an immunohistochemical study that demonstrated that the giant cells in this lesion are osteoclasts.23 Harris presented 4 cases that responded positively to calcitonin.24 Using calcitonin as a complementary treatment for the aggressive form of the lesion reduces the chances of sequelae.1 In the present case, the lesion was extensive and involved several teeth; using calcitonin prior to surgery may have reduced the size of the tumor, thereby making the resection less extensive. Extensive, more aggressive, or recurring lesions require ample surgical resection, which may lead to a substantial bone defect and the loss of several teeth, affecting both esthetics and function.9,25 Maxillary defects can be challenging from the standpoint of rehabilitation. Prosthetic rehabilitation after the surgical resection of such lesions in the maxilla is performed to close the bone defect, separate the nasal passage from the oral cavity, and reestablish the patient’s ability to chew, speak, and swallow.26 In the present case, complete enucleation of the lesion required removing several teeth and making a temporary RPD, followed by a definitive denture for esthetic/functional rehabilitation. Conclusion Dentists play an important role in both the diagnosis of CGCL and its treatment, which involves the removal of the lesion and the reestablishment of the functions of the stomatognathic system. Author information Dr. Pellicioli is a master’s candidate, Department of Oral Pathology, Dental School, Federal University of Rio Grande do Sul, Porto Alegre, Brazil, where Drs. General Dentistry www.agd.org Marco Martins, Carrard, and Manoela Martins are assistant professors. Dr. Kaefer is a master’s candidate, Department of Oral Pathology, School of Dentistry, Federal University of Santa Maria, Brazil. References 1. Borges HO, Machado RA, Vidor MM, Beltrao RG, Heitz C, Filho MS. Calcitonin: a non-invasive giant cells therapy. Int J Pediatr Otorhinolaryngol. 2008;72(7):959963. 2. de Lange J, van den Akker HP, Veldhuijzen van Zanten GO, Engelshove HA, van den Berg H, Klip H. Calcitonin therapy in central giant cell granuloma of the jaw: a randomized double-blind placebo-controlled study. Int J Oral Maxillofac Surg. 2006;35(9):791-795. 3. Nicolai G, Lore B, Mariani G, Bollero P, de Marinis L, Calabrese L. Central giant cell granuloma of the jaws. J Craniofac Surg. 2012;21(2):383-386. 4. De Lange J, Van den Akker HP. Clinical and radiological features of central giant-cell lesions of the jaw. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2005; 99(4):464-470. 5. Tamrikulu R, Erol B, Yilmaz U, Yaman F, Atilgan S. Central giant cell lesions (CGCL) of the jaws in children - the review of 34 cases. Biotechnol Biotechnologic Equip. 2007;21(2):211-214. 6. Stavropoulos F, Katz J. Central giant cell granulomas: a systematic review of the radiographic characteristics with the addition of 20 new cases. Dentomaxillofac Radiol. 2002;31(4):213-217. 7. Heithersay GS, Cohn SA, Parkins DJ. Central giant cell granuloma. Aust Endod J. 2002;28(1):18-23. 8. Stern M, Eisenbud L. Management of giant cell lesions of the jaws. Oral Maxillofacial Clin North Am. 1991;3: 165-177. 9. Speight P. Pathology and genetics of head and neck tumours. In: Barnes L EJ, Reichart P, Sidransky D, eds. World Health Organization Classification of Tumours. Lyon, France: IARC Press; 2005:185-186. 10. Infante Cossio P, Martinez de Fuentes R, Carranza Carranza A, Torres Lagares D, Gutierrez Perez JL. Recurrent central giant cell granuloma in the mandible: surgical treatment and dental implant restoration. Med Oral Patol Oral Cir Bucal. 2007;12(3):E229-E232. 11. Sezer B, Koyuncu B, Gomel M, Gunbay T. Intralesional corticosteroid injection for central giant cell granuloma: a case report and review of the literature. Turk J Pediatr. 2005;47(1):75-81. 12. Tosco P, Tanteri G, Iaquinta C, et al. Surgical treatment and reconstruction for central giant cell granuloma of the jaws: a review of 18 cases. J Craniomaxillofac Surg. 2009;37(7):380-387. 13. Ustundag E, Iseri M, Keskin G, Muezzinoglu B. Central giant cell granuloma. Int J Pediatr Otorhinolaryngol. 2002;65(2):143-146. 14. Kauzman A, Li SQ, Bradley G, Bells RS, Wunder JS, Kandel R. Central giant cell granuloma of the jaws: assessment of cell cycle proteins. J Oral Pathol Med. 2004;33(3):170-176. 15. Chuong R, Kaban LB, Kozakewich H, Perez-Atayde A. Central giant cell lesions of the jaws: a clinicopathologic study. J Oral Maxillofac Surg. 1986;44(9):708713. 16. Yamaguchi T, Dorfman HD. Giant cell reparative granuloma: a comparative clinicopathologic study of lesions in gnathic and extragnathic sites. Int J Surg Pathol. 2001;9(3):189-200. 17. Motamedi MH, Eshghyar N, Jafari SM, et al. Peripheral and central giant cell granulomas of the jaws: a demographic study. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2007;103(6):e39-e43. 18. Chavali LV, Bhimalingam RM, Sudhakar PV. Cherubism—a case report with long term follow up. Indian J Pathol Microbiol. 2011;54(4):793-795. 19. Whitaker SB, Waldron CA. Central giant cell granulomas of the jaw. A clinical radiologic and histologic study. Oral Surg Oral Med Oral Pathol. 1993;75(2): 199-208. 20. Kruse-Losler B, Diallo R, Gaertner C, Mischke KL, Joos U, Kleinheinz J. Central giant cell granuloma of the jaws: a clinical, radiologic, and histopathologic study of 26 cases. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2006;101(3):346-354. 21. Minic A, Stajcic Z. Prognostic significance of cortical perforation in the recurrence of central giant cell granulomas of the jaws. J Craniomaxillofac Surg. 1996; 24(2):104-108. 22. Bataineh AB, Al-Khateeb T, Rawashdeh MA. The surgical treatment of central giant cell granuloma of the mandible. J Oral Maxillofac Surg. 2002;60(7):756-761. 23. Flanagan AM, Tinkler SM, Horton MA, Williams DM, Chambers TJ. The multinucleate cells in the giant cell granulomas of the jaw are osteoclasts. Cancer. 1988; 62(6):1139-1145. 24. Harris M. Central giant cell granulomas of the jaws regress with calcitonin therapy. Br J Oral Maxillofac Surg. 1993;31(2):89-94. 25. Lee H, Ercoli C, Fantuzzo JJ, Girotto JA, Coniglio JU, Palermo M. Oral rehabilitation of a 12-year-old patient diagnosed with a central giant cell granuloma using a fibula graft and an implant-supported prosthesis: a clinical report. J Prosthet Dent. 2008;99(4):257-262. 26. Segal A. Rehabilitation of a maxillary defect secondary to recurrent giant cell granuloma. J Prosthodont. 2011;20(Suppl 2):S32-S37. www.agd.org General Dentistry January/February 2015 e19 Diagnosis and Treatment Planning Alveolar ridge splitting for implant placement: a review of the procedure and report of 3 cases Prakash S. Talreja, MDS n Chandrashekhar R. Suvarna, BDS n Preeti P. Talreja, MDS In long-standing edentulous cases, the alveolar bone generally demonstrates vertical and horizontal atrophy. Rehabilitating these patients with dental implants is difficult unless treatment is accompanied by some kind of augmentation procedures, all of which include specific disadvantages. One such technique, alveolar ridge splitting, is suitable only for enhancing ridge width. It has the advantage of reducing treatment time significantly, as implants can E be placed simultaneously. This article offers a brief description of the procedure along with 3 case reports. Received: January 30, 2013 Accepted: May 7, 2013 Key words: augmentation, ridge split, implant, piezoelectric, osteotome, chisel vidence has shown the success of implant-based replacement of missing teeth.1,2 However, rehabilitating patients with implants can be impeded by horizontal and vertical atrophy of the alveolar ridge, especially in long-standing edentulous cases. In such cases, alveolar ridge augmentation is necessary for adequate insertion of implants. Augmentation procedures include block grafting, guided bone regeneration, or distraction osteogenesis, all of which have disadvantages, such as increased treatment cost and time, as well as surgical morbidity related to second donor site. In recent years, alveolar ridge splitting has been successfully used to prepare the atrophic maxilla and mandible for implant insertion and augmentation.1-4 Alveolar ridge splitting is suitable only for enhancing the width of the edentulous ridge. It is accomplished by making a longitudinal osteotomy Fig. 1. (Case No. 1) Reflection of a full thickness flap to expose the narrow ridge. Fig. 2. (Case No. 1) Using the piezoelectric saw to create horizontal and vertical corticotomy. Fig. 3. (Case No. 1) Using a tapered osteotome for ridge expansion. Fig. 4. (Case No. 1) Implants placed in the expanded ridge. e20 January/February 2015 General Dentistry www.agd.org Fig. 5. (Case No. 1) Placement of splinted porcelain-fused-to-metal (PFM) crowns. Fig. 6. (Case No. 2) Implant placed in the expanded ridge. Fig. 7. (Case No. 2) Placement of the PFM prosthesis. in the atrophic alveolar bone, followed by lateral repositioning of the buccal cortex using a greenstick fracture.1 The space created between the buccal and lingual/palatal cortical plate is filled with autologous, allogenic, or alloplastic graft material—or without any graft material.5-8 When used in the maxilla, this technique results in significantly reduced treatment time compared to other options, as implants are generally placed simultaneously along with the ridge split. Alveolar ridge splitting is well-suited for the maxilla, where the medullary bone is soft and the cortical bone is thin, which allows for easy expansion of the buccal cortex.9 The technique can be carried out in the mandible as well, although the risk of buccal plate fracture increases, as the thicker cortical plate makes the bone less flexible. Hence, in the mandible, a staged approach is recommended.10 This article presents 3 cases, each of which involved splitting a narrow alveolar ridge. In 2 cases, implants were placed in the maxilla simultaneously; the third case involved delayed implant placement in the mandible. Clinical examination of the cases revealed severe bone resorption of the edentulous area. The reduced dimension of the alveolar bone was confirmed through a cone beam computed tomography scan. The procedure was explained to the patients and written consents were obtained. Originally, the ridge split technique involved creating a sagittal osteotomy of the edentulous ridge using instruments (such as chisels) between the 2 cortical plates to expand the ridge and allow implant placement.1 Subsequently, various approaches to this procedure have been developed.5,6,11-13 The technique used in the cases presented in this article involved the use of a piezoelectric saw, small chisel, twist drill, and tapered osteotomes to expand the buccal plate as carefully as possible to avoid its fracture. Threaded, self-tapping Osstem implants (marketed in the US as HIOSSEN Dental Implants, HIOSSEN, Inc.) with resorbable blast media surface were placed in predetermined osteotomies. Implants of any diameter and length can be placed using this technique. However, if multiple implants are placed adjacent to each other, splinting of the implants in the final prosthesis is recommended. Case No. 1 A 45-year-old woman sought to replace her missing maxillary left canine and first premolar with dental implants. After local anaesthesia was administered, a crestal incision (slightly to the palatal side) was made, followed by 2 diverging vertical incisions on the line angles of the neighboring teeth. A full-thickness mucoperiosteal flap was reflected to expose the underlying bone. The palatal flap was raised minimally to maintain blood supply to the bone (Fig. 1). Using a piezoelectric saw (Mectron s.p.a.), rectangular corticotomies were made. The crestal horizontal corticotomy was made 1 to 2 mm from the adjacent teeth (Fig. 2). Next, 2 vertical corticotomies were made on the buccal cortical www.agd.org plate, extending from the edges of the initial midcrestal corticotomy. The length of the horizontal corticotomy is dictated by the number of implants to be placed and the distance between the implants, while the length of the vertical corticotomy is usually 50% of the length of the implant to be placed. Next, the buccal segmented plate was slowly dislocated in the buccal direction by placing a small chisel in the horizontal corticotomy and striking it carefully with a mallet. A twist drill was used to mark the implant’s position and depth; tapered osteotomes were then used to expand the buccal plate to the required depth (Fig. 3). Care was taken to follow the path established by the twist drill in the bone. A gentle, slow, rotating motion was used to increase the separation of plates by the osteotomes. Two Osstem implants were placed with good primary stability in the newly created osteotomies. The cover screws were placed next (Fig. 4) and the implants were submerged for undisturbed healing for a period of 6 months. The widened space between the cortical plates was filled with a mix of autogenous bone and alloplastic bone grafting material (PerioGlas, NovaBone Products, LLC). The periosteum was released on the inner surface of the buccal flap, and the tissue was approximated using 3-0 black braided silk suture (Mersilk, Ethicon, Inc.). The patient was instructed not to wear any dentures or to place pressure on the healing site. Second stage surgery was performed 6 months later. The implants were exposed, healing abutments were placed (with tissue approximated around them) and allowed to heal for 2 weeks. Subsequently, an implant level impression was obtained, and splinted porcelain-fused-to-metal (PFM) crowns were delivered to the patient (Fig. 5). Case No. 2 A 35-year-old man sought to replace his missing maxillary left lateral incisor with a dental implant. A procedure similar to that described in the first case was performed and the implant was placed simultaneously with the split ridge (Fig. 6). Second stage surgery was performed 6 months later; at that time, a PFM prosthesis was delivered (Fig. 7). General Dentistry January/February 2015 e21 Diagnosis and Treatment Planning Alveolar ridge splitting for implant placement Fig. 8. (Case No. 3) Photograph showing the missing mandibular teeth, after an inferior horizontal corticotomy and ridge expansion. Fig. 9. (Case No. 3) Implants placed in the regenerated bone between the expanded cortical plates. Fig. 10. (Case No. 3) Final implant-supported fixed partial denture. Case No. 3 surgery, which involved exposing the implants, placing healing abutments, and positioning an apically displaced flap to increase the width of attached gingiva around the implant. An implantsupported PFM fixed partial denture was delivered after a healing period of 4 weeks (Fig. 10). success rates of 86.2%-97.5%.14 A systematic review by Aghaloo & Moy calculated a 97.4% survival rate for the ridge splitting technique.15 In the 3 case reports presented here, there was complete patient satisfaction in terms of esthetics and function. In all the cases, 6-month postprosthesis intraoral periapical radiographs showed stable bone levels around the implants. Long-term follow-up, which involves recalling the patients once every 6 months for clinical and radiographic examination, is recommended for this technique. Corticotomies during the ridge splitting procedures have been performed using a variety of instruments, including a No. 15 blade, beaver blade, razor-sharp chisel, round bur, fissure bur, diamond disk, reciprocal saw, and piezoelectric devices. In the cases presented here, a series of instruments were used to expand the bone gently and to avoid the risk of buccal plate fracture. Using a piezoelectric device allows for more precise, safer corticotomies compared to a conventional rotary bur or reciprocating saw.16,17 As previously described, the maxilla is well-suited for ridge splitting, as thinner cortical plates and softer medullary bone allows for easier expansion of the maxillary ridge. By contrast, the mandible has denser cortical plates and less cancellous bone, making it difficult to perform this procedure without the risk of buccal plate fracture. However, the posterior mandible can be split in cases with favorable conditions, such as a long edentulous span, cancellous bone between the dense outer cortical plates, and a good bone A 36-year-old woman sought to replace her missing mandibular left premolars and left first molar with dental implants. Compared to the maxillary bone, the mandibular bone has less flexibility due to its thicker cortical plates; thus a slightly modified technique was used to split the ridge and avoid malfracture of the osteotomized segment. This modification involved extending the length of the vertical corticotomies to match the length of the predetermined implants. In addition, an inferior horizontal corticotomy was made by connecting the caudal ends of the vertical corticotomies. Using chisels and osteotomes, the buccal segmented plate was gently dislocated to the buccal side (Fig. 8) and the space between the 2 plates was filled with a mix of autogenous bone and PerioGlas. Achieving primary stability was uncertain in this case; hence it was decided to place the implant after a healing period of 6 months. Mersilk was used and a tension-free closure of the surgical site was achieved. To avoid pressure on the surgical site, the patient was instructed not to wear any dentures. At the end of 6 months, the site was re-entered under local anesthesia and complete regeneration of new bone between the separated buccal and lingual plates was confirmed. Implant osteotomies were prepared conventionally per the manufacturer’s instructions and 2 Osstem implants were placed (Fig. 9). A tension-free closure of the surgical site was achieved and the patient was recalled 3 months later for second stage e22 January/February 2015 Discussion The ridge split technique is one of several options available for ridge augmentation. The technique allows simultaneous implant placement in most cases, thus reducing the overall treatment time.1-4 Moreover, as it involves expansion of the buccal plate, the correction of buccal concavity resulting from ridge resorption can be achieved in some cases. Morbidity related to second donor site may be eliminated as well. Adequate bone height is a prerequisite for this procedure, as splitting the crest does not increase bone volume vertically.1 Although skilled surgeons can perform splitting and expansion for very thin ridges, a minimum ridge width of 3 mm with some cancellous bone is preferred.9 A pyramidal ridge form with a wider base is ideal for this technique as it prevents the risk of buccal plate fracture. Predictable results have been obtained with this technique. In a 2006 literature review, Chiapasco et al evaluated different augmentation procedures for rehabilitating deficient edentulous ridges and found that ridge expansion techniques had a reported surgical success rate of 98%-100%.14 By comparison, implants had a survival rate of 91.0%-97.3%, with General Dentistry www.agd.org height above the mandibular canal.9 If the buccal plate fractures, the mobile plate can be retained with bone fixation screws.7 In the third case presented in this article, a slightly different approach was employed for ridge splitting in the mandible, with an additional, inferior corticotomy connecting the vertical corticotomy. This step allowed for easier expansion and minimized any chance of bone fracture. The technique of ridge splitting usually is performed simultaneously with implant placement, as doing so reduces the overall treatment time.18.19 However, simultaneous implant placement can result in complications, such as lack of initial implant stability, fracture of the buccal segmented bone, and compromised implant placement in the buccolingual and apicocoronal direction.19 When the primary stability of the implants is compromised, an interpositional bone graft can be placed between the expanded cortices and implants can be placed after the healing period of the augmented site.5,11 Alternatively, complications can be avoided by using a staged approach.10,16,19 In the third case report presented here, there was concern about achieving adequate primary stability; hence the implants were placed after healing of the augmented site was completed. For the cases presented in this article, the intercortical area was filled with a mixture of autogenous bone and alloplastic bone grafting material. Although some dentists may prefer to place particulate bone grafting materials around the implants and in the intercortical space, it has been reported that a bone graft usually is unnecessary.2,7,8,12,16 A barrier membrane was not used, as periosteum is believed to be the best possible biologic membrane, containing a rich supply of osteogenic cells.18 Conclusion Ridge splitting is a predictable, effective technique for the horizontal augmentation of narrow edentulous ridges. Proper case selection and careful clinical maneuvering during the procedure result in a successful surgical and prosthetic outcome. Unless a general dentist is well-trained to carry out the ridge split procedure, referral to an oral surgeon/periodontist is recommended. Author information Dr. Prakash Talreja is an assistant professor, Department of Periodontology and Implantology, Bharati Vidyapeeth Deemed University Dental College and Hospital, Navi Mumbai, India. Dr. Suvarna is in private practice in Mumbai, India. Dr. Preeti Talreja is an associate professor, Department of Oral Medicine and Radiology, Yerala Medical Trust Dental College and Hospital, Navi Mumbai, India. References 1. Simion M, Baldoni M, Zaffe D. Jawbone enlargement using immediate implant placement associated with a split-crest technique and guided tissue regeneration. Int J Periodontics Restorative Dent. 1992;12(6):462-473. 2. Scipioni A, Bruschi GB, Calesini G. The edentulous ridge expansion technique: a five-year study. Int J Periodontics Restorative Dent. 1994;14(5):451-459. 3. Engelke WG, Diederichs CG, Jacobs HG, Deckwer I. Alveolar reconstruction with splitting osteotomy and microfixation of implants. Int J Oral Maxillofac Implants. 1997;12(3):310-318. 4. Chiapasco M, Ferrini F, Casentini P, Accardi S, Zaniboni M. Dental implants placed in expanded narrow edentulous ridges with the Extension Crest device: a 1-3-year multicenter follow-up study. Clin Oral Implants Res. 2006(3);17:265–272. 5. Lustmann J, Lewinstein I. Interpositional bone grafting technique to widen narrow maxillary ridge. Int J Oral Maxillofac Implants. 1995;10(5):568-577. 6. Duncan JM, Westwood RM. Ridge widening for the thin maxilla: a clinical report. Int J Oral Maxillofac Implants. 1997;12(2):224-227. 7. Basa S, Varol A, Turker N. Alternative bone expansion technique for immediate placement of implants in the edentulous posterior mandibular ridge: a clinical report. Int J Oral Maxillofac Implants. 2004;19(4):554-558. www.agd.org 8. Scipioni A, Bruschi GB, Giargia M, Berglundh T, Lindhe J. Healing at implants with and without primary bone contact. An experimental study in dogs. Clin Oral Implants Res. 1997;8(1):39-47. 9. Misch CM. Implant site development using ridge splitting techniques. Oral Maxillofac Surg Clin North Am. 2004;16(1):65-74, vi. 10. Enislidis G, Wittwer G, Ewers R. Preliminary report on a staged ridge splitting technique for implant placement in the mandible: a technical note. Int J Oral Maxillofac Implants. 2006;21(3):445-449. 11.Summers RB. The osteotome technique: part 4— future site development. Compend Contin Edu Dent. 1995;16(1):1090-1099. 12. Coatoam GW, Mariotti A. The segmental ridge-split procedure. J Periodontol. 2003;74(5):757-770. 13. Blus C, Szmukler-Moncler S. Split-crest and immediate implant placement with ultra-sonic bone surgery: a 3-year life-table analysis with 230 treated sites. Clin Oral Impl Res. 2006:17(6):700-707. 14. Chiapasco M, Zaniboni M, Boisco M. Augmentation procedures for the rehabilitation of deficient edentulous ridges with oral implants. Clin Oral Implants Res. 2006;17(Suppl 2):136-159. 15. Aghaloo TL, Moy PK. Which hard tissue augmentation techniques are the most successful in furnishing bony support for implant placement? Int J Oral Maxillofac Implants. 2007;22(Suppl):49-70. 16. Elian N, Jalbout Z, Ehrlich B, et al. A two-stage full-arch ridge expansion technique: review of the literature and clinical guidelines. Implant Dent. 2008;17(1):16-23. 17. Sohn DS. Color Atlas, Clinical Applications of Piezoelectric Bone Surgery. Seoul, South Korea: Kunja Publishing; 2008. 18. Guirado JL, Yuguero MR, Carrion del Valle MJ, Zamora GP. A maxillary ridge-splitting technique followed by immediate placement of implants: a case report. Implant Dent. 2005;14(1):14-20. 19. Sohn DS, Lee HJ, Heo JU, Moon JW, Park IS, Romanos GE. Immediate and delayed lateral ridge expansion technique in the atrophic posterior mandibular ridge. J Oral Maxillofac Surg. 2010;68(9):2283-2290. Manufacturers Ethicon, Inc., Somerville, NJ 877.384.4266, www.ethicon.com HIOSSEN, Inc., Fairless Hills, PA 888.678.0001, www.hiossen.com Mectron s.p.a., Carasco, Italy 39.0185.351374, dental.mectron.com NovaBone Products, LLC, Jacksonville, FL 386.462.7660, www.novabone.com General Dentistry January/February 2015 e23 Prosthodontics/Removable Management of severe mandibular deviation following partial mandibular resection: a case report Husain Harianawala, BDS, MDS n Mohit Kheur, BDS, MDS n Supriya Kheur, BDS, MDS n Jay Matani, BDS, MDS Extensive mandibular resection commonly leads to a deviation of the mandible, facial disfigurement, and difficulty with speech and mastication. The rehabilitation of these patients is a prosthodontic challenge. This article presents the case of a 60-year-old man who sought prosthetic rehabilitation after a right segmental mandibulectomy. The prosthetic rehabilitation was planned in 2 phases. A palatal ramp was constructed, followed by a mandibular guiding flange. After S urgical removal of a malignant neoplasm is the most common cause of partial mandibular loss.1 Patients treated for tumors of the head and neck can suffer from morbidity and disability, induced mainly by surgical resection, radiation, and chemotherapy.1 The degree of disability depends on tumor location and size, the duration and quantity of radiation therapy, type of reconstruction, and the patient’s age and medical status. Tumor resection should be as conservative as possible, with the goal of preserving the condyle and teeth in the vicinity, primary reconstruction, implant placement, and, in some cases, intermaxillary fixation.2 Recent case reports have reported using dental implants in the rehabilitation of completely or partially edentulous patients who have undergone mandibular resection.3,4 Physiotherapy should be started immediately after surgery to prevent scar formation and trismus. Other factors that may have an impact on the prognosis are the structure and volume of resected tissue, whether the mandibular resection is combined with a partial or complete glossectomy, and/ or whether a partial pharyngectomy is required.5 Clinicians need to be aware that these patients may also be impacted by psychological and social difficulties postsurgery.6 Surgeons must work in conjunction with prosthodontists to formulate a reconstruction plan that will best allow the patient to lead a healthy, dignified life. An interdisciplinary approach is required to manage facial disfigurement, distorted speech, salivation, deglutition, occlusal disharmony, and the psychosocial issues that e24 January/February 2015 4 months, the patient’s chewing ability, tongue movement, and facial esthetics were improved. Received: August 22, 2013 Revised: December 20, 2013 Accepted: January 30, 2014 Key words: hemimandibulectomy, guiding flange prosthesis, palatal ramp, rehabilitation can accompany a mandibular resection.6 This article describes the case of a patient who underwent a hemimandibulectomy and highlights the multidisciplinary approach and prosthetic management. Case report A 60-year-old man reported to the M.A. Rangoonwala College of Dental Sciences & Research Centre hospital in Pune, India with the chief complaint of loose teeth in the right posterior mandibular region. Careful examination and investigation led to the diagnosis of a squamous cell carcinoma lesion, extending from the mandibular first molar to the anterior border of the ramus. Following discussions with the hospital’s Head & Neck Cancer Team, a radical neck dissection with a segmental hemimandibulectomy was performed. Primary reconstruction with a rigid fixation plate and a pectoralis major myocutaneous (PMMC) flap was performed successfully (Fig. 1). Periodontally compromised maxillary teeth that would be in the line of the oncology radiation treatment were extracted at the time of surgery. The surgical resection was followed by a 5-week radiation regimen consisting of 6000 rads and 33 cycles. Prosthetic rehabilitation began 1 month postsurgery. The patient had a dental midline deviation of 2.1 cm to the right side, and was unable to occlude in maximum intercuspation despite manual guidance (Fig. 2). Diagnostic impressions were made with a modified stock impression Fig. 1. Radiographic presentation following surgical reconstruction. General Dentistry www.agd.org 21 mm Fig. 2. Anterior photograph showing mandibular deviation. Fig. 5. Anterior photograph showing gradual correction of deviation. tray with irreversible hydrocolloid (Dentalign, Prime Dental Products Pvt. Ltd.) and poured in Type III dental stone (KAL Rock, Kalabhai Karson Pvt. Ltd.). The patient had carious root stumps, but declined to have them extracted following his major surgery. Periodontal therapy (including oral prophylaxis and root planing) was followed by restoring the carious lesions on the remaining teeth. Given the extensive midline deviation, the treatment plan was divided into 2 phases: correction of the mandibular deviation followed by definitive prosthetic treatment for longterm comfort and function. Phase 1 A long lever arm and a compromised tissue bed on the resected side of the patient’s mouth would create excessive prosthetic movement. An angular pathway of closure would induce lateral forces which could dislodge the denture.7 Because of these factors, a palatal ramp was selected as the first step to correct the deviation.8 Fig. 4. Palatal ramp in situ. Fig. 3. Palatal ramp prosthesis on the model. Fig. 6. Cast of partial denture design. A heat-cured acrylic record base (DPI RR Heat Cure, Dental Products of India) was fabricated with a wrought wire circumferential clasp on the anterior abutment tooth and an Adams clasp over the first molar. The palatal ramp was fabricated by adding an autopolymerizing resin (DPI RR Cold Cure, Dental Products of India) to the palatal aspect of the record base on the non-resected side and manually guiding the mandible closer to the maximum intercuspal position within physiologic limits. To ensure smooth gliding of the mandible, minor adjustments were made, followed by finishing and polishing procedures (Fig. 3). The patient was instructed to use the palatal ramp for at least 2 hours a day for 5 days, gradually increasing the duration after the fifth day (Fig. 4). The patient was recalled for the next reline only after he was completely comfortable with the palatal ramp prosthesis. The deviation was corrected with 7 relines over a period of 16 weeks until the maximum intercuspal position was achieved on the non-resected www.agd.org side of the mouth (Fig. 5). Occlusal equilibration was performed and the ramp was adjusted for a final time. The patient was asked to wear the prosthesis until he felt no strain in the temporomandibular joint and surrounding musculature. Phase 2 The second phase of rehabilitation began after the patient had become comfortable with and accustomed to the palatal ramp. To maintain the mandible in the correct position against the maxilla, a mandibular cast partial denture was fabricated with a buccal guiding flange on the nonresected side. The cast partial denture was designed so as to employ alternating buccal and lingual retentive clasp arms on successive posterior teeth on the non-resected side of the mouth (Fig. 6). Reciprocating arms were planned to have a bracing effect on these teeth. To achieve maximum support, rest seats were planned for all posterior teeth, in addition to an interrupted linguoplate major connector to brace all General Dentistry January/February 2015 e25 Prosthodontics/Removable Management of severe mandibular deviation following partial mandibular resection Fig. 7. Trial framework of partial denture to determine jaw relationship. of the mandibular anterior teeth and a proximal plate minor connector adjacent to every edentulous span. The lattice-type minor connector for the outrigger was kept short to reduce the leverage effect in the partial denture while providing enough lip support for improved esthetics. The minor connector extension (for supporting the guiding flange) was extended from the buccal extensions of the embrasure clasps and the edentulous span. The angulation of the minor connector on the buccal flange was adjusted on the cast. Both arches were prepared for the cast partial denture. To increase the retention, stability, and support of the mandibular denture, the maximal extension of the lingual flange—within physiologic limits—was ensured on the non-resected side. A polyether adhesive (Polyether Tray Adhesive Refill, 3M ESPE) was applied over the custom autopolymerized resin tray. Next, a polyether impression (Impregum, 3M ESPE) was made and poured in type IV gypsum (Ultra Rock, Kalabhai Karson Pvt. Ltd.). A framework cobalt-chromium alloy (IPS d.Sign, Ivoclar Vivadent, Inc.) was fabricated. Autopolymerizing resin was added over the minor connector overlying the outrigger to act as a custom tray. Next, a functional impression was made using a low-fusing compound, followed by a secondary impression using a lightbodied condensation silicone (Speedex, Coltene/Whaledent, Inc.). An altered cast was poured using the Type III dental stone. Record bases and occlusal rims were fabricated over the minor connectors. The jaw relation was recorded and transferred e26 January/February 2015 Fig. 8. Try-in of partial denture. Fig. 9. Final partial denture in situ. onto a semi-adjustable articulator (Hanau Wide-Vue, Whip Mix Corporation) (Fig. 7). Care was taken to reduce the frontal plane rotation of the residual mandible, which is known to occur due to muscle imbalance that can occur after mandibular resection. As the patient’s lips and cheeks were pulled medially due to scarring, the denture teeth were placed buccal to the crest of the ridge on the non-resected side and lingually at a higher level on the resected side (Fig. 8).9 With a lateral resection, bilateral occlusal contacts serve as a stabilizing factor and mastication is confined to the non-resected site. During the try-in stage, the buccal extension of the cast partial frame was relined with autopolymerizing resin to verify the jaw relation. Heat-cured fiber-reinforced resin (Triplex Hot, Ivoclar Vivadent, Inc.) was used as the final denture base material. A laboratory remount was followed by finishing and polishing of the cast partial denture; at which point, the prosthesis was delivered to the patient (Fig. 9). General Dentistry www.agd.org The patient was instructed to wear the mandibular denture for 1 hour/day for the first week, then increase its use gradually. He reported difficulty masticating during the initial period; however, mastication improved over time, and the patient was satisfied with the esthetic result of the treatment. The patient made regular recall visits during which the health of the abutment teeth and the partial denture were re-evaluated. The tissue surface of the outrigger was relined 6 months post-treatment when increased fibrosis was seen in the PMMC flap. Discussion Rehabilitation of patients who have undergone mandibular resection is a greater clinical challenge compared to patients with maxillary defects. In the present case, the mandibular deviation was very large due to the extended radiotherapy postsurgery. Correcting such a mandibular deviation against the forces of the musculature and sclerosing tissue requires a significant lateral force. The palatal ramp prosthesis over the maxillary arch was chosen to correct the deviation as it provided a larger base for stability and support of the prosthesis. The acrylic plate also made it easy and convenient to reline the palatal ramp regularly until the maximum intercuspal position was achieved. After the deviation was corrected and stabilized, a guiding flange prosthesis was placed over the mandibular arch as the final restoration. This design was selected because it had a reduced bulk and offered negligible interference to tongue movements compared to other types of prostheses, thus improving speech and overall comfort. The success of this treatment has led the authors to treat other cases using a similar protocol. Conclusion Reconstructing a mandibular defect by means of microvascular free flaps allows the maxillofacial prosthodontist to achieve a more effective rehabilitation.10,11 It is critical to both manage the mandibular deviation and provide psychological counseling to the patient.6 Proper multidisciplinary treatment planning allows dentists to place osseointegrated implants strategically in patients with a reconstructed mandible, restoring occlusal and masticatory function while also achieving an acceptable esthetic result. Author information Drs. Harianawala and Matani are researchers and practioners, Department of Prosthodontics, M.A. Rangoonwala College of Dental Sciences & Research Centre, Pune, India, where Dr. M. Kheur is a professor. Dr. S. Kheur is a professor, Dr. D. Y. Patil Dental College, Pimpri, India. References 1. Beumer J III, Marunick MT, Esposito SJ. Maxillofacial Rehabilitation: Surgical and Prosthodontic Management of Cancer-Related Acquired, and Congenital Defects of the Head and Neck. 3rd ed. Hanover Park, IL: Quintessence Publishing Co.; 2011. 2. Schneider RL, Taylor TD. Mandibular resection guidance prostheses: a literature review. J Prosthet Dent. 1986;55(1):84-86. 3. Sistos RJ, Jimenez CR, Benavides RA. Prosthetic and surgical treatment of patient previously subjected to hemi-mandibulectomy. Rev Odont Mex. 2013;17(1): 42-46. 4. Sravanthi Y, Rathod A, Deepa KL, Priyadarshini I. Rehabilitation of mandibulectomy patient with an overdenture: a case report. Ind J Pub Health Res Dev. 2013; 4(2):297-300. 5. Robinson JE, Rubright WC. Use of a guide plane for maintaining the residual fragment in partial or hemimandibulectomy. J Prosthet Dent. 1964;14(5): 992999. www.agd.org 6. Rehmani AA. The complete rehabilitation of patient with lateral mandibular defect. J Ind Prosthodont Soc. 2002;29-32. 7. Beumer J III, Curtis TA, Marunick MT. Maxillofacial Rehabilitation: Prosthodontic and Surgical Consideration. St. Louis: Ishiyaku Euroamerica; 1996. 8. Adisman K. Prosthetic reconstruction of a resected mandible. J Prosthet Dent. 1962;12:384-392. 9. Kokubo Y, Fukushima S, Sato J, Seto K. Arrangement of artificial teeth in the neutral zone after surgical reconstruction of the mandible: a clinical report. J Prosthet Dent. 2002;88(2):125-127. 10. Shaw RJ, Sutton AF, Cawood JI, et al. Oral rehabilitation after treatment for head and neck malignancy. Head Neck. 2005;27(6):459-470. 11. Kanan RY, Mathur BS, Tzafetta K. Single flap reconstruction for complex oro-facial defects using chimeric free fibular flap variants. J Plast Reconstr Aesthet Surg. 2013;66(3):358-363. Manufacturers Coltene/Whaledent, Inc., Cuyahoga Falls, OH 330.916.8800, www.coltene.com Dental Products of India, Mumbai, India 99.22.22079351, www.dpi.co.in Ivoclar Vivadent, Inc., Amherst, NY 800.533.6825, www.ivoclarvivadent.us Kalabhai Karson Pvt. Ltd., Mumbai, India 91.22.2578.1823, www.kalabhai.com Prime Dental Products Pvt. Ltd., Maharashtra, India 91.72601.47129, www.prime-dental.com Whip Mix Corporation, Louisville, KY 800.626.5651, whipmix.com 3M ESPE, St. Paul, MN 888.364.3577, solutions.3m.com General Dentistry January/February 2015 e27 Diagnosis of Oral Pathology Rare oral cartilaginous choristoma: a case report and review of the literature Marina Lara de Carli, DDS, PhD n Felipe Fornias Sperandio, DDS, PhD n Fernanda Rafaelly de Oliveira Pedreira, DDS n Alessandro Antonio Costa Pereira, DDS, PhD n Joao Adolfo Costa Hanemann, DDS, PhD Cartilaginous choristomas are extraosseous benign tumors. They occur in abnormal sites that usually do not contain chondrocytes. The oral variant of this entity is considered to be very rare, with only 38 cases currently published in the literature. This article presents a case of an oral cartilaginous choristoma lesion. In addition to presenting clinical and histological diagnoses, this article compares the present case to recently reported cases. Special attention was given to analyzing cells of the oral cartilaginous choristoma, which appear as well-differentiated chondrocytes with O ral cartilaginous choristoma is a very rare extraosseous chondroma that is found usually on the tongue.1-3 Although its origins are a topic of debate (and may include metaplastic and also developmental derivations), a cartilaginous choristoma shows benign behavior and generally does not recur after a simple excisional procedure.2,4-7 This slow-growing and asymptomatic mass may resemble other oral benign soft tissue tumors; as a result, a histological evaluation must eliminate the possibility of clinically similar lesions based on the characteristic appearance of the chondroma’s cells.6,8 Case report This case study was conducted in compliance with the Helsinki Declaration on medical research protocols and ethics. Permission was granted by the Alfenas Federal University Institutional Review Board. The patient signed an informed consent agreement. A 59-year-old man had an asymptomatic nodular lesion (2 years duration) located in the dorsum of the tongue. The patient reported that the lesion’s size had not changed since it was first noticed. The patient`s systemic condition was normal and he reported that no previous trauma had occurred in the area. The extraoral examination was uneventful, while the intraoral assessment revealed a single, flaccid, round, sessile nodule in the posterior third of the tongue dorsum. The lesion had a yellowish color with erythematous borders and was e28 January/February 2015 a pale blue cytoplasm surrounded by a light basophilic stroma and no evidence of malignity. Following surgical excision, the lesion did not recur, which is similar to other reported cases of oral cartilaginous choristomas. Received: September 30, 2013 Revised: January 14, 2014 Accepted: March 6, 2014 Key words: choristoma, hyaline cartilage, biopsy, tongue well-circumscribed, measuring 10 mm in diameter (Fig. 1). No other lesions were observed in the oral cavity. An excisional biopsy of the lesion was performed under local anesthesia and the obtained specimen was fixed in 10% buffered formalin and embedded in paraffin wax. Next, 5 μm-thick sections were obtained and stained (H&E). The histopathological analysis showed that the lesion was located in the oral submucosa and encapsulated completely by dense fibrous connective tissue (Fig. 2). The lesion consisted of a benign proliferation of welldeveloped chondrocytes—exhibiting small and highly basophilic nuclei—inserted in a mature hyaline matrix (Fig. 3). Based on these findings, the lesion was diagnosed as a cartilaginous choristoma of the tongue. The postoperative period was uneventful, and there were no signs or symptoms of reoccurrence at a 4-month follow-up (Fig. 4). Fig. 1. Photograph of a sessile yellowish nodule with erythematous borders on the dorsum surface of the patient’s tongue. Fig. 2. Photomicrograph of the surgical specimen showing a mature hyaline cartilage tissue separated from the adjacent skeletal muscle and overlying squamous epithelium by a thin capsule of fibrous connective tissue (H&E, magnification 50X). General Dentistry www.agd.org Discussion The histological appearance of a cartilaginous choristoma resembles that of benign chondromas; however, choristomas occur in sites that usually do not contain chondrocytes.3,6,8 As a result, cartilaginous choristomas are rare soft tissue lesions that occur mostly on the hands and feet.9 Conversely, the very rare oral cartilaginous choristoma is Fig. 3. Photomicrograph showing small chondrocytes with a clear cytoplasm and round nuclei (H&E, magnification 400X). Fig. 4. Photograph of the patient’s tongue 4 months post-treatment with no signs of recurrence. Table. Comparison of 3 recent case reports of oral cartilaginous choristoma and the present study.7,13,14 Source Patient Duration (years/gender) (years) Location Size (mm) Follow-up (months/recurrence) Shibasaki et al (2013) 25/female 1.5 Lower lip 20 36/no recurrence Pereira et al (2012) 64/female >5 Dorsum, midline left, posterior third 5 9/no recurrence Saha et al (2011) 11/female 11 NA Present case (2015) 59/male 2 Dorsum, midline 10 right, posterior third NA NA 4/no recurrence Abbreviation: NA, not available. usually found on the tongue (mainly in the lateral borders).1,8 According to the literature, a number of conditions may indicate a clinical differential diagnosis for cartilaginous choristoma.6,8 Sialoliths and pleomorphic adenomas have been found; however they are rare in this region. Neurofibromas, schwannomas, and granular cell tumors are more common and were considered as differential diagnoses in the present case. The oral cartilaginous choristoma is generally not considered as a clinical diagnosis due to its rarity. A granular cell tumor is a relatively rare lesion in the dorsal region of the tongue. It occurs in all age groups, but most frequently in patients 40-60 years of age. This lesion is thought to arise from Schwann cells and characteristically has a yellowish color.10 A single asymptomatic, slow-growing nodule on the tongue (10-20 mm) also may represent a schwannoma or a neurofibroma—benign tumors that originate from the nerve sheath. A neurofibroma presents with a hamartomatous hyperplasic appearance.11,12 These tumors should be treated with excision and usually have low rates of reccurrence.10-12 Previously, only 37 cases of oral cartilaginous choristomas had been published in the literature.7,8,13,14 In their 2012 literature review, Norris & Mehra reviewed 34 cases and designated the most significant clinical aspects of this lesion.8 Based on the literature, an oral cartilaginous choristoma occurs most frequently in the tongue and usually does not show inclinations based on age or gender.4 In the present case, the choristoma was also found on the patient’s tongue and had no significant clinical differences compared to previously reported cases. A literature review of 3 recent cases confirmed the lesion’s predilection for the tongue (Table).7,13,14 www.agd.org In the present case, an excisional biopsy was conducted. A follow-up visit 4 months post-treatment showed no signs or symptoms of recurrence. Histologically, the present case had no other mesenchymal tissue except for the mature cartilage. Previous cases in the literature (including extraoral choristomas) reveal that these tumors often exhibit a variety of mesenchymal tissues along with the chondrocyte cells, such as adipose and bony tissues.1,8,15 In the present case, the tumor consisted solely of chondrocytes. According to the literature, immunohistochemical studies may serve as an additional resource to characterize the chondrocytes found in the choristoma while also helping to distinguish between the rare cartilaginous choristoma and other soft oral benign lesions. Calcium-binding proteins (such as S100) are expressed by both choristomas and oral schwannomas. Cytokeratins and the epithelial membrane antigen usually are present in pleomorphic adenomas; these markers are not found in cartilaginous choristomas.5,6,13,16 In addition, calponin and muscle-specific actins are not expressed by choristomas; this may help to distinguish them from inflammatory myofibroblastic tumors.17 The present case was very easily diagnosed as an encapsulated mass of mature chondrocytes inserted in a hyaline matrix residing in the oral submucosa. The cellular and nuclear morphology of the chondrocytes was examined to eliminate the possibility of the rare chondrosarcoma of the tongue, a condition that may also be included in a differential diagnosis due to its similar location, size, and nodular-shaped growth.6,18-20 Typically, no mitotic figures can be distinguished in the analyzed field of the choristoma and the cells should be represented (as with an intraosseous maxillary chondroma) by well-differentiated chondrocytes surrounded by light basophilic stroma.15 Individually, these chondrocytes should have a pale blue cytoplasm with no evidence of malignancy. Oddly shaped chondrocytes (either binucleated or with pleomorphic nuclei) usually suggest a malignant lesion, such as a chondrosarcoma.21,22 In addition, chondrosarcoma cells show varying mitotic activity and frequently are arranged in lobules separated by thin fibrous septa; in addition, occasional calcification may occur within the lesion.21,23 General Dentistry January/February 2015 e29 Diagnosis of Oral Pathology Rare oral cartilaginous choristoma: a case report and review of the literature Conclusion When diagnosing painless, slow-growing, nodular lesions located on the tongue, dentists should take care to distinguish (both clinically and histologically) between oral choristomas and malignant neoplasms. Author information Dr. de Carli is a postdoctoral candidate, Department of Clinic and Surgery, School of Dentistry, Alfenas Federal University, Minas Gerais, Brazil, where Dr. Pedreira is a master’s candidate, Dr. Hanemann is a professor, and Drs. Sperandio and Pereira are professors, Institute of Biomedical Sciences. References 1.Sera H, Shimoda T, Ozeki S, Honda T. A case of chondroma of the tongue. Int J Oral Maxillofac Surg. 2005; 34(1):99-100. 2.Matsushita K, Tahara M, Sato H, Nakamura E, Fujiwara T. Cartilaginous choristoma deep in the upper midline oral vestibule. Br J Oral Maxillofac Surg. 2004;42(5): 436-438. 3.Chou LS, Hansen LS, Daniels TE. Choristomas of the oral cavity: a review. Oral Surg Oral Med Oral Pathol. 1991;72(5):584-593. 4.Munro JM, Singh MP. Chondroma of the tongue. Report of a case and a consideration of the histogenesis e30 January/February 2015 of such lesions. Arch Pathol Lab Med. 1990;114(5): 541-542. 5.Toida M, Sugiyama T, Kato Y. Cartilaginous choristoma of the tongue. J Oral Maxillofac Surg. 2003;61(3):393396. 6.Rossi-Schneider TR, Salum FG, Cherubini K, Yurgel LS, Figueredo MA. Cartilaginous choristoma of the tongue. Gerodontology. 2009;26(1):78-80. 7.Shibasaki M, Iwai T, Chikumaru H, Inayama Y, Tohnai I. Cartilaginous choristoma of the lower lip. J Craniofac Surg. 2013;24(2):e192-e194. 8.Norris O, Mehra P. Chondroma (cartilaginous choristoma) of the tongue: report of a case. J Oral Maxillofac Surg. 2012;70(3):643-646. 9.Chung EB, Enzinger FM. Chondroma of soft parts. Cancer. 1978;41(4):1414-1424. 10.Speight P. Pathology and genetics of head and neck tumours. In: Barnes L EJ, Reichart P, Sidransky D, eds. World Health Organization Classification of Tumours. Lyon, France: IARC Press; 2005:185-186. 11.Cohen M, Wang MB. Schwannoma of the tongue: two case reports and review of the literature. Eur Arch Otorhinolaryngol. 2009;266(11):1823-1829. 12.Marocchio LS, Oliveira DT, Pereira MC, Soares CT, Fleury RN. Sporadic and multiple neurofibromas in the head and neck region: a retrospective study of 33 years. Clin Oral Investig. 2007;11(2):165-169. 13.Pereira GW, Pereira VD, Pereira Junior JA, da Silva RM. Cartilaginous choristoma of the tongue with an immunohistochemical study. BMJ Case Rep. 2012. 14.Saha R, Tandon S, Kumar P. Chondroid choristoma: report of a rare case. J Clin Pediatr Dent. 2011;35(4): 405-407. General Dentistry www.agd.org 15.Scivetti M, Maiorano E, Pilolli GP, et al. Chondroma of the tongue. Clin Exp Dermatol. 2008;33(4):460462. 16.Santos PP, Freitas VS, Pinto LP, Freitas Rde A, de Souza LB. Clinicopathologic analysis of 7 cases of oral schwannoma and review of the literature. Ann Diagn Pathol. 2010;14(4):235-239. 17.Salgueiredo-Giudice F, Fornias-Sperandio F, MartinsPereira E, da Costa dal Vechio AM, de Sousa SC, dos Santos-Pinto-Junior D. The immunohistochemical profile of oral inflammatory myofibroblastic tumors. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2011; 111(6):749-756. 18.Forman G. Chondrosarcoma of the tongue. Br J Oral Surg. 1967;4(3):218-221. 19.Al-Rawi M, Harper T, Bafakih F. Chondrosarcoma of the tongue: a case report and a review of the literature. Laryngoscope. 2013;123(2):418-421. 20.Angiero F. Extraskeletal myxoid chondrosarcoma of the left buccal mucosa. Anticancer Res. 2012;32(8):33453350. 21.Gallego L, Junquera L, Fresno MF, de Vicente JC. Chondrosarcoma of the temporomandibular joint. A case report and review of the literature. Med Oral Patol Oral Cir Bucal. 2009;14(1):E39-E43. 22.Takahama A Jr., Alves Fde A, Prado FO, Lopes MA, Kowalski LP. Chondrosarcoma of the maxilla: report of two cases with different behaviours. J Craniomaxillofac Surg. 2012;40(3):e71-e74. 23.Goutzanis L, Kalfarentzos EF, Petsinis V, Papadogeorgakis N. Chondrosarcoma of the mandibular condyle in a patient with Werner syndrome: a case report. J Craniomaxillofac Surg. 2013;41(7):e170-e174. AGD on Facebook Like the AGD Facebook page and gain access to breaking general dentistry news, AGD event photos, important links, and more! Keep the conversation going with the AGD on all of your favorite social media sites—and be a part of the latest general dentistry news as it’s happening! Diagnosis and Treatment Planning Atypical presentation of salivary mucocele: diagnosis and management Kumar Nilesh, MDS n Jagadish Chandra, MDS A mucocele is a common pathological lesion involving the minor salivary glands. It usually presents as an asymptomatic small superficial swelling over the lower labial mucosa. However, uncommon variants of oral mucoceles sometimes occur. Such lesions may be difficult to diagnose due to their unusual size and atypical clinical presentation. This article describes the case of a deeply embedded large mucocele over the buccal mucosa. Ultrasonography was used to visualize the O ral mucoceles are common lesions of the minor (accessory) salivary glands.1 Clinically, an oral mucocele presents as a soft, bluish to transparent cystic swelling below the mucosa. Mucoceles can appear at any site where minor salivary glands are present. However, they are most commonly seen on lower lips, and are rarely >1.5 cm in diameter.2 Because of the typical oral mucocele presentation, a large mucocele at an unusual site may cause a diagnostic dilemma. The article presents a case of a large buccal mucocele, and its presentation, diagnosis, and surgical removal. Case report A 30-year-old man presented with the chief complaint of a painless intraoral swelling over the left buccal mucosa. The size and position of the lesion, and aspiration was used to help in the eventual diagnosis. An intraoral approach was used in the complete removal of the lesion. Received: September 24, 2013 Accepted: January 13, 2014 patient first noticed the swelling approximately 1 year earlier. Since then, the swelling had grown gradually to its size at presentation. A clinical examination of the patient’s face showed a nontender oval swelling of approximately 1.5 cm behind the corner of the mouth (Fig. 1). The skin overlying the lesion was normal and “pinchable.” Intraoral examination revealed a dome-shaped swelling of approximately 4 cm in diameter occupying almost the entire left buccal mucosa (Fig. 2). The swelling was nontender, soft, and fluctuant on palpation, with normal overlying mucosa. The patient’s oral hygiene was poor, and he was missing his mandibular left first molar. The cervical lymph nodes were not palpable. No significant medical history or history of trauma were reported by the patient. Fig. 1. Facial photograph showing extraoral swelling. e32 January/February 2015 Key words: mucocele, buccal mucosa, surgical excision General Dentistry www.agd.org The overall clinical presentation was suggestive of a benign submucosal lesion and the differential diagnosis was a lipoma, fibroma, dermoid cyst, or mucocele. Ultrasonography was advised to study the nature, size, and extent of the lesion. The ultrasonogram showed a hypoecogenic oval mass of 42 x 33 x 24 mm within the buccal subcutaneous tissue (Fig. 3). Based on this radiological assessment, a diagnosis of a fluid-filled cystic lesion was established. Aspiration of the cystic fluid was carried out under local anesthesia, using an 18 gauge needle. Four ml of a white, viscous fluid was aspirated and sent for cytochemical evaluation. The fluid consisted of mucus and numerous inflammatory cells. Chemical analysis of the aspirated fluid showed increased amylase and protein counts. Fig. 2. Anterior photograph showing large intraoral swelling occupying almost the entire left buccal mucosa. 2 1 Fig. 3. Ultrasonogram showing a hypoecogenic oval mass within the buccal subcutaneous tissue. Fig. 4. Surgical removal of lesion. Left. Line diagram showing the incision design: linear incision placed over the buccal mucosa along the occlusal plane (1); Stensen duct on the buccal mucosa needs to be identified and preserved (2). Right. Lesion exposed completely by submucosal blunt dissection. 1 2 1 2 Fig. 5. Histopathology. Left. Section showing mucin pooling along with mucinophages (1) surrounded by a fibrous connective tissue capsule (2) (H&E, magnification 10X). Center. Section showing lining of the lesion (1) with associated minor salivary glands (2) (H&E, magnification 10X). Right. Section at higher magnification showing large vacuolated cells with empty cytoplasm (white arrow) and mucinophages (gray arrow) (H&E, magnification 40X). Based on the clinical, radiological, and cytochemical evaluations, a final diagnosis of buccal mucocele was established. Surgical excision of the lesion by intraoral approach was executed under local anesthesia. After attaining adequate anesthesia, a linear incision of approximately 3 cm was made over the buccal mucosa, keeping it parallel to the occlusal plane. Care was taken to indentify and preserve the opening of the Stensen duct over the buccal mucosa (usually present on the buccal mucosa opposite the crown of the maxillary first molar). Submucosal blunt dissection was elected to free the lesion from the surrounding tissue (Fig. 4). The excised lesion was sent for histopathological evaluation. The microscopic examination revealed a fibrous capsule with central pooling of mucin along with mucinophages. Associated minor salivary glands were also noted (Fig. 5). The histopathological analysis confirmed the diagnosis of a salivary mucocele. At a 2-year follow-up, the patient showed complete healing of the surgical site with no recurrence. Discussion Etiopathogenesis and types Mucoceles are cavities filled with mucus and lined by epithelium or covered by granulated tissue.1,3 Based on its etiopathogenesis, mucoceles can be classified as extravasation or retention types. An extravasation mucocele is caused by trauma to the excretory duct of a minor salivary gland. Trauma causes rupture of the duct, resulting in extravasation and accumulation of saliva in the surrounding connective tissue. An extravasation cyst consists of a central pool of extravasated mucus surrounded by granulation tissue (such as a pseudocyst). Unlike extravasation cysts, retention cysts result from ductal obstruction due to sialolithiasis, periductal scars, or invasive tumors. The narrowing of the ductal opening does www.agd.org not allow an adequate salivary flow, with subsequent ductal distention presenting as a mucosal swelling.4 Clinical presentation Clinically, mucoceles present as asymptomatic swellings over the oral mucosa. They are usually small in size, with a mean diameter of <1 cm.1 They affect both genders in all age groups, with the peak age of incidence between 10 and 29 years.1,2 The lower lip is the most common site, although they can be found in any region where there are salivary glands. However, they are more rare in the palate, retromolar space, and the buccal mucosa.5 In a review of 1824 cases of oral mucoceles, Chi et al reported the incidence to be highest on the lip (82%), followed by floor of the mouth (6%), ventral tongue (5%), buccal mucosa (5%), palate (1%), and reteromolar region (<1%).6 The present case was uncommon in view of its large size and location on the buccal mucosa. General Dentistry January/February 2015 e33 Diagnosis and Treatment Planning Atypical presentation of salivary mucocele: diagnosis and management Investigation and diagnosis A mucocele with its usual presentation can be easily diagnosed based on its clinical appearance. However, an unusual presentation—in relation to its size and location—may require further evaluation. Ultrasonography or other advanced diagnostic methods (such as magnetic resonance imaging) are extremely helpful in visualizing the form, diameter, and position of the lesion relative to adjacent organs.7 Ultrasonography in the present case showed a hypoecogenic oval mass within the subcutaneous tissue underlying the buccal mucosa. Fine needle aspiration is a useful diagnostic technique for evaluating patients with salivary gland nodules and enlargement. Differentiating between mucoceles and vascular lesions preoperatively is very important—if a large angioma is mistaken for a mucocele, the excision of the vascular lesion can result in major bleeding.8 Management Surgery remains the mainstay for treatment of oral mucoceles. Three possible surgical approaches are the complete excision of the lesion, excision along with removal of associated salivary gland tissues, and marsupialization (for a large lesion in close proximity to vital structures). Other techniques reported in the literature include cryotherapy, laser (such e34 January/February 2015 as erbium or carbon dioxide), intralesional corticosteroids, topical γ-linolenic acid, and intralesional sclerosing agent.9-13 Surgical excision was chosen for the present case to allow for the complete removal of the lesion and subsequent histopathological evaluation to confirm the diagnosis. Conclusion The presentation of a typical oral mucocele results in a simple diagnosis. When an atypical presentation occurs, however, it is important to evaluate and investigate the lesion in a stepwise manner to reach a definitive diagnosis. Oral mucocele should be included as a differential diagnosis for any submucosal swelling over the buccal mucosa. Recognizing these variants is important to avoid misdiagnosis. Author information Dr. Nilesh is a reader, School of Dental Sciences, Krishna Institute of Medical Sciences, Karad, India. Dr. Chandra is a professor, Yenepoya Dental College & Hospital, Mangalore, India. References 1. Baurmash HD. Mucoceles and ranulas. J Oral Maxillofac Surg. 2003;61(3):369-378. 2. Ata-Ali J, Carrillo C, Bonet C, Balaguer J, Penarrocha M, Penarrocha M. Oral mucocele: review of the literature. J Clin Exp Dent. Available at: http://www. medicinaoral.com/odo/volumenes/v2i1/jcedv2i1p18. pdf. Accessed October 27, 2014. General Dentistry www.agd.org 3. Guimaraes MS, Hebling J, Filho VA, Santos LL, Vita TM, Costa CA. Extravasation mucocele involving the ventral surface of the tongue (glands of Blandin-Nuhn). Int J Paediatr Dent. 2006;16(6):435-439. 4. Cecconi D, Achilli A, Tarozzi M, et al. Mucoceles of the oral cavity: a large case series (1994-2008) and a literature review. Med Oral Patol Oral Cir Bucal. 2010;15(4):e551-e556. 5. Cataldo E, Mosadomi A. Mucoceles of the oral mucous membrane. Arch Otolaryngol. 1970;91(4):360365. 6. Chi AC, Lambert PR, Richardson MS, Neville BW. Oral mucoceles: a clinicopathologic review of 1,824 cases, including unusual variants. J Oral Maxillofac Surg. 2011;69(4):1086-1093. 7. Shah GV. MR imaging of salivary glands. Magn Reson Imaging Clin N Am. 2002;10(4):631-662. 8. Layfield LJ, Gopez EV. Cystic lesions of the salivary glands: cytologic features in fine-needle aspiration biopsies. Diagn Cytopathol. 2002;27(4):197-204. 9. Bodner L, Tal H. Salivary gland cysts of the oral cavity: clinical observation and surgical management. Compendium. 1991;12(34):150, 152, 154-156. 10. Yague-Garcia J, Espana-Tost AJ, Berini-Aytes L, GayEscoda C. Treatment of oral mucocele-scalpel versus CO2 laser. Med Oral Patol Oral Cir Bucal. 2009;14(9): e469-e474. 11. Iyer VH, Moorthy V, Ramalingam P. 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