Creating a Fixed Herbst Appliance in a Complete Digital Workflow

3Shape Orthodontics Solutions
By: Dr Santiago Isaza Penco
Stefano Negrini, Owner Tridentestense Ortodonzia Srl
Creating a Fixed Herbst Appliance
in a Complete Digital Workflow
3D technologies for Orthodontics are rapidly changing the way we work. With advanced intraoral scanners
achieving accurate impressions of full bites in the clinic, and CAD/CAM systems in labs that can efficiently create appliances of exceptional quality, orthodontic businesses can no longer ignore the economic and practical
benefits that derive from the new digital methods.
In this article, Doctor Isaza Penco and Stefano Negrini describe production of a Herbst appliance in a complete
digital workflow.
Stage 1 – The patient’s first visit in the clinic
The workflow begins by taking photographs of the
patient’s face, over jet and lateral radiographs and
cephalometry at the orthodontic clinic. (See picture 1)
The doctor then captures the patient’s intraoral situation
by scanning with the 3Shape TRIOS® to take a digital
impression. (See picture 2)
Systems and tools used in the workflow
• 3Shape TRIOS® Digital Impression Solution
(Intraoral scanner)
• 3Shape Ortho Analyzer™
• 3Shape Appliance Designer™
• EOS Sintering Machine M270™
Picture 1 Patient’s face, over jet and
lateral radiographs and cephalometry
Stage 2 – Digitally dispatching the case to the lab
The digital impression is then sent to the orthodontic
laboratory together with the general clinical indications
via the internet. The lab can preview the case and immediately contact the clinic if they wish to discuss details
or suggest additional scanning while the patient is still
in the chair. This instant communication and interaction
online was unthinkable with traditional methods.
they can:
• Design the bands for the upper and lower jaw
• Determine the material thickness and friction
the parts should have on the dental elements; as
well undercuts compensation and cement space.
• Control interferences with the antagonist. If
requested by the clinic, they can preserve the
contact areas. See (picture 4)
The clinic uses 3Shape Ortho Analyzer to digitally
archive the case, create study models, analyze,
measure, apply a virtual articulator to adjust the
occlusion to the treatment plan (see picture 3), and pack
all this information in a file folder for sending to the lab.
Stage 4 – Production of the appliance
The STL files containing the retention design are
exported to a production center for manufacturing of the
bands and the models. Chrome Cobalt Laser sintering is
used for the appliance parts and resin or plastic is used
for the master models.
Stage 3 – Designing the Herbst Appliance using 3D
CAD software
3Shape’s Appliance Designer™ is a dedicated CAD program. The lab technicians create the design in order to
realize the bands that will serve as a support for the
Herbst hinge. Using the software’s tools
When the lab receives all the parts, it will carefully
check the fit of the rough steel elements on the
model - including insertion and removal functionality.
The lab will then polish (picture 6) and assemble the
Herbst attachments by means of laser welding
3Shape Orthodontics Solutions
By: Dr Santiago Isaza Penco
Stefano Negrini, Owner Tridentestense Ortodonzia Srl
Picture 2 Intra oral scan of the patient using TRIOS
Picture 3 Adjusting the occlusion in a virtual articulator using
3Shape Ortho Analyzer software
Picture 4 Designing the bands, while setting optimal thickness
and friction in Appliance Designer
Picture 5 Lower band design
(picture 7) – according to the technical and functional
specifications as well as the clinical indications of the
appliance.
Conclusion
Finally, the completed appliance and its documentation
are sent to the dental clinic for fitting in the
patient’s mouth.
Stage 5 – Fitting of the appliance
The dental clinic receives the appliance and calls
the patient in for fitting. The doctor will:
1. Check the fit of the bands in the patient’s mouth
and their stability before cementing.
2. Make any adjustments if needed.
3. Perform final cementation.(see picture 8)
6
Picture 6 Lower bands produced in chrome
cobalt via laser sintering after polishing
The digital workflow provides a range of advantages in
terms of cost savings, fit of appliance, fast turnaround,
and new ways for clinics and labs to work together towards optimal results for the patient. As with the whole
dental industry, intraoral scanning and CAD/CAM technologies are defining the future of orthodontics.
This article was first published in: Lebendige Wissenschaft-Spitzenforschung Kieferorthopädie, Sept. 2013,
ISSN: 1861-4620,
by: Dr Santiago Isaza Penco Stefano Negrini, Owner
Tridentestenze Ortodonzia Srl, Creating a Fixed Herbst
Appliance in a Complete Digital Workflow.
7
Picture 7 Bands fitted with attachments
by laser welding
8
Picture 8 Appliance cemented in
patient’s mouth