Multiloop edgewise archwire in the treatment of a patient with an

CLINICIAN’S CORNER
Multiloop edgewise archwire in the treatment of
a patient with an anterior open bite and a long
face
Gerson Luiz Ulema Ribeiro,a Saulo Regis, Jr,b Tais de Morais Alves da Cunha,b Marcos Adriano Sabatoski,b
Odilon Guariza-Filho,c and Orlando Motohiro Tanakad
Florianópolis, Santa Catarina, and Curitiba, Paraná, Brazil
An adolescent girl with an Angle Class III malocclusion, excessive lower facial height, and anterior open bite
sought nonsurgical treatment. She was treated with a multiloop edgewise archwire (MEAW). In association
with a chincup, MEAW mechanics allowed the successful correction of the anterior open bite and the molar
relationship, without major alterations of the patient’s profile. Combined orthodontic and surgical treatment
should be considered for patients with skeletal anterior open-bite malocclusion. For patients who do not
want surgery, however, MEAW treatment is an alternative that can have excellent results. (Am J Orthod
Dentofacial Orthop 2010;138:89-95)
A
n anterior open bite malocclusion is a difficult
problem in orthodontic treatment.1,2 Because
of separate occlusal planes for the maxillary
and mandibular dentitions, the open bite would be
configured by the anterior divergence of these planes,
instead of the overlap seen in normal occlusion.3 This
malocclusion is usually associated with internal derangement of the temporomandibular joint.4
Most patients with anterior open bites have both
a dentoalveolar component and increased skeletal vertical dimension.5,6 The true skeletal open-bite patient
would require a combination of orthodontic treatment
and orthognathic surgery to achieve a stable occlusion,
acceptable esthetics, and improved function.7 However,
surgery can be too expensive for some patients, and
others refuse to consider such an invasive intervention.8
The orthodontist’s only choice will be to deny treatment
or try to resolve as much of the malocclusion as possible
with orthodontic treatment alone.
a
Adjunct professor, Graduate Dentistry Program in orthodontics, Federal
University of Santa Catarina, Florianópolis, Santa Catarina, Brazil.
b
Postgraduate student, Dentistry Graduate Program in orthodontics, Pontifical
Catholic University of Paraná, Curitiba, Paraná, Brazil.
c
Associate professor, Graduate Dentistry Program in orthodontics, Pontifical
Catholic University of Paraná, Curitiba, Paraná, Brazil.
d
Professor, Graduate Dentistry Program in orthodontics, Pontifical Catholic
University of Paraná, Curitiba, Paraná, Brazil.
The authors report no commercial, proprietary, or financial interest in the
products or companies described in this article.
Reprint requests to: Orlando Motohiro Tanaka, Pontifical Catholic University of
Paraná, Graduate Dentistry Program, Orthodontics, R Imaculada Conceição,
1155, 80215-901, Curitiba, PR, Brazil; e-mail, [email protected].
Submitted, December 2007; revised and accepted, March 2008.
0889-5406/$36.00
Copyright Ó 2010 by the American Association of Orthodontists.
doi:10.1016/j.ajodo.2008.03.036
The multiloop edgewise archwire (MEAW) was
introduced by Kim3; he had already been using it for almost 2 decades. This technique has been successfully
applied for treatment of severe open-bite malocclusions.
The objectives of treatment include proper vertical positioning of the maxillary incisors, compatible cant of
the maxillary and mandibular occlusal planes, and uprighted inclination of the posterior teeth. The form of
the MEAW is primarily that of an ideal edgewise archwire with the addition of boot loops.3 The vertical loop
component serves as a break between the teeth, gives
flexibility to the archwire, and allows horizontal control of the tooth positions.9 The horizontal component
gives more flexibility and provides vertical control. It
is 2.5 times the length of wire in ordinary archwires
and provides a 10-fold reduction in the loaddeflection rate. The use of MEAW requires completion
of all leveling and alignment, elimination of all poorly
positioned brackets, and constant use of vertical elastics on the anterior teeth. It was originally prescribed
for brackets with .018-in slots and .016 3 .022-in
archwires, allowing more flexibility for intrusive
forces.3
This article shows a successful treatment result in
a growing patient with an Angle Class III subdivision
malocclusion and an anterior open bite.
CASE REPORT
A girl, aged 14 years 8 months, was referred by her
clinician to a private office after consulting 2 other orthodontists, with the complaint of an anterior open
bite. She had a pleasant profile, although there was
89
90
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Fig 1. Pretreatment records: skeletal Class I, Angle Class III subdivision malocclusion with anterior
open bite, mandibular midline deviation, protrusion of mandibular incisors, straight profile, and minimal maxillary incisor exposure when smiling.
increased lower facial height and little incisor exposure during smiling (Fig 1). She had an Angle Class
III subdivision malocclusion, with an anterior open
bite of 3.5 mm, an overjet of 0.5 mm, and a midline
diastema. The mandibular dental midline was deviated
to the left by 1.5 mm. Cephalometric analysis showed
a skeletal Class I relationship (ANB angle, 4 ) and
a high mandibular plane angle (FMA, 32 ). The maxillary incisors to NA angle was 19 ; the maxillary incisors to NA distance was 4 mm; the anterior inferior
teeth were protruded, with mandibular incisors to NB
angle was 42 ; and the mandibular incisors to NB distance wa 9 mm.
Several factors have been implicated as causes of an
anterior open-bite malocclusion, including inherited facial form, unfavorable growth pattern, posture, sucking
habits, nasopharyngeal airway obstruction, and tongue
posture and function.1 Kim3 reported that the association of an inclined occlusal plane and mesial tipping
of posterior teeth might cause an anterior open bite. In
some cases, open bite is more likely to be produced
by the interaction of different functional aspects and
environmental influences with facial morphology.1
Our patient had a hyperdivergent facial profile but no
history of sucking habits, mouth breathing, or abnormal
tongue posture or swallowing.
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91
Fig 2. High-pull chincup and edgewise fixed appliance, 0.022-in slot with 0.019 3 0.026-in stainless
steel MEAW with gradual increase in boot-loop size. Intermaxillary elastics mechanics and finishing
produced a satisfactory intercuspation.
The main objective of open-bite treatment in general
is to achieve ideal overbite and overjet relationships.
The vertical reference for anterior teeth would be the
position of the maxillary central incisor relative to the
inferior lip line.3 When treating an open-bite malocclusion, correction of the maxillary and mandibular occlusal planes and the axial inclinations of the teeth must be
considered.1,3 Therefore, the orthodontist’s choice to
intrude the molars or extrude the anterior teeth will be
guided mainly by the vertical dimension of the lower
face and the esthetic features of the anterior segment.
This patient’s Angle Class III malocclusion would
be corrected by uprighting the mandibular posterior
teeth and using intermaxillary elastics, with Class III resulting on the right side. A high-pull chincup would
need to be worn 16 hours a day. Ideal overjet and overbite would be achieved by extruding the maxillary and
mandibular anterior teeth, and also correcting the posterior tooth inclination, resulting in correction of the
reverse curve of Spee in the mandibular arch. Because
the patient had little maxillary central incisor exposure
during smiling, the anterior tooth extrusion would also
favor a more esthetic result. Delicate control of the
facial height would be required.
Full edgewise fixed appliances with 0.022-in slot
brackets were placed. During the alignment and leveling stages, the patient wore a vertical chincup (16 hours
a day) to prevent extrusion of the posterior teeth (Fig 2).
A .019 3 .026-in stainless steel archwire, made with
boot loops in all interproximal areas from the lateral
incisors to the second molars, was used. On each loop,
we checked lingual root torque, bilateral symmetry,
and vertical-segment angulations to prevent gingival injuries. Tip-back bends were incorporated. The curve of
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Fig 3. Posttreatment records show good intercuspation, overjet, overbite, anteroposterior relationship, canine guidance, and root apex integrity.
Spee in the maxillary arch was increased and reversed in
the mandible. The tip-back bends and the Spee curves
provided intrusive forces on the maxillary and mandibular incisors, an effect opposed by 3/16-in elastics with
vertical force placed in the canines’ mesial loops. These
elastics delivered a 50-g force with the mouth closed
and 150 g with moderate mouth opening.
After bite closure and finishing, the treatment objectives were achieved, and the appliances were removed
(Fig 3). Treatment time was 3 years. An Angle Class I
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Table.
Cephalometric analysis
Measurement
Norm Pretreatment Posttreatment
SNA ( )
82
80
SNB ( )
2
ANB ( )
Convexity
0
Y-axis
59.9
Facial
87.8
32
SN-GoGn ( )
25
FMA ( )
90
IMPA ( )
22
Maxillary incisor-NA ( )
Maxillary incisor-NA (mm)
4
25
Mandibular incisor-NB ( )
Mandibular incisor-NB (mm)
4
1-1
130
1A-Po
1
LS-S
0
LI-S
0
75
Z angle ( )
84
80
4
11
60
89
42
32
97
19
4
42
9
130
1
0
1
75
85
81
4
12
60
89
41
33
83
11
2
27
7
136
5
0
0
79
molar relationship was achieved on both sides, and
overjet, anterior open bite, and mandibular midline deviation were all corrected. As intended, the facial profile
was maintained, and the incisors’ exposure during smiling increased.
A slight increase of the mandibular plane angle
(FMA, from 32 to 33 ) was verified. The maxillary
and mandibular incisors were more upright (IMPA,
from 97 to 83 ). Other cephalometric changes are
reported in the Table.
At the follow-up appointment 5 years after treatment, stability of the dental and skeletal vertical dimension as well as the overjet and overbite could be seen
(Fig 4).
DISCUSSION
The patient had a hyperdivergent skeletal pattern
and anterior open bite with some dental component, excessive lower facial height, and vertical growth trend.
Treatment for such patients includes managing growth.
Cangialosi5 suggested that most patients with anterior
open bite have skeletal and dentoalveolar features contributing to the malocclusion. Not all skeletal open-bite
subjects have negative overbite.10 The distinction between a skeletal and a dental open-bite malocclusion
is a practical matter because there should be different
approaches for each condition to obtain an effective
and stable treatment result.8
Various therapeutic modalities have been proposed
for the treatment of anterior open-bite malocclusion in
both growing and nongrowing patients, depending on
the treatment objectives. Conventional orthodontic-
93
orthopedic treatment has been directed at inhibiting vertical maxillary growth with headgear, retarding mandibular growth with chincups, and extruding anterior teeth
with vertical elastics.11,12 Some other methods that have
been used include tongue-crib therapy for habit control,
posterior bite-blocks, posterior magnets, magnetic
active vertical corrector, and functional appliances.1
Orthodontic treatment of patients with skeletal open
bite consists of intruding the posterior teeth or preventing their further eruption with the intention to control
anterior facial height. The vertical position of the dentition is greatly influenced by the teeth and alveolar process and their adaptation to the jaw relationship. This
facilitates the correction of overbite and overjet by
orthodontic movement alone.
A great challenge in treating an anterior open bite is
the control of anchorage when molar intrusion is
required.2 Devices usually proposed are high-pull headgear, lingual arches, functional appliances, and posterior bite-blocks.8 Carano et al13 primarily reported the
use of a new device for rapid molar intrusion. An effective way to intrude molars is to use skeletal anchorage
with titanium screws.2,8
Kuroda et al,14 in a study comparing treatment outcomes with molar intrusion using skeletal anchorage
and orthognathic surgery, demonstrated no significant
difference in both treatment results in terms of reducing
facial heights and increasing overbite.
MEAW therapy for anterior open-bite malocclusion
has been demonstrated to be effective for the treatment
of this malocclusion. Kim et al,1 evaluating its longterm stability, found no significant relapse in a 2-year
follow-up. This mechanism was able to retract and
extrude the anterior teeth and to upright the posterior
teeth.1,8 It is a good option for orthodontic treatment
of skeletal open bite, although the technique has little
or no effect on the skeletal pattern.8
There is no agreement about the ability to intrude
posterior teeth in the literature, although there are few
studies about the effects of MEAW on the dentition.1,8
The disadvantages of the MEAW approach are the
requirement of high professional skills and the great
dependence on patient compliance for treatment success.
CONCLUSIONS
Orthodontic treatment combined with surgery
should be considered for patients with a skeletal anterior
open-bite malocclusion, but the patient’s choice must be
respected. The MEAW appliance was shown to have an
excellent treatment outcome, achieving the proposed
goals, although this technique required excellent professional ability.
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Fig 4. Long-term stability at the 5-year follow-up, with maintenance of adequate overbite and overjet. The third molars were extracted.
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