Townie Treatment Case: A Team Approach by Dr. David R. Boschken

Categories: Orthodontics;
Townie Treatment Case: A Team Approach 

Treating a complex Class III case with segmented clear aligners, elastics, high-frequency vibration and virtual visits


by Dr. David R. Boschken


March 1, 2020, was a disruptive day: California issued a shelter-in-place order that would stay in effect for 3½ months. This resulted in a sharp decline in dental care use, which persisted for many months.1 During practice closure, demand for teledentistry options increased 60-fold1 but not all practices were ready for the absolute digital adoption that would be required to help them survive the shutdown and following months. Some authors report that patients treated with fixed appliances during the COVID-19 pandemic had more problems and emergency visits than clear aligner patients.2,3 This discrepancy in emergency visits may have been related to issues with wires or brackets, while aligners can be disposed of and replaced with the next sequential or previous aligner as needed.

With the disruption of in-office visits for patients, there was a need for properly managing patients’ treatment needs while maintaining proper protocols required by shelter-in-place regulations and COVID-19. Our offices had already made the transition to Invisalign’s digital platform, which includes a suite of tools that help capture data and digital imaging, create treatment plans, direct the fabrication of clear aligners and retainers, and allow doctors to monitor and communicate with patients remotely.

For my practice, the most indispensable tool ended up being Invisalign’s Virtual Care system. Being able to monitor my patients’ progress remotely let the practice ensure continuity of care while minimizing physical contact. During 2020, we used Virtual Care with more than 300 cases, which allowed patient treatment to occur with no in-office visitation after the initial consultation and setup appointments. One such case is presented here.

Diagnosis and etiology

A 24-year-old patient with a Class III skeletal/dental malocclusion (Fig. 1) came in concerned about his anterior crossbite. He presented with a retrognathic maxilla and slight prognathic mandible, mild upper (2 mm) and lower (1 mm) crowding, anterior crossbite, 10% overbite, mandible deviated to the left (2 mm), lower midline shifted to the left (2 mm), missing teeth #1, #16, #17 and #32, and moderate lower anterior facial recession (1–2 mm).

Panoramic radiography (Fig. 2) noted a generalized reduction of 1–2 mm in lower anterior alveolar bone levels and confirmed the patient was missing third molars from previous extractions.

The lateral cephalogram (Fig. 3) and Wits analysis (Fig. 4) confirmed a Class III skeletal pattern (ANB -3.9 degrees and Wits Appraisal -8.6 mm) because of mandibular prognathism (SNB 83 degrees) and maxillary retrognathism (SNA 79.1 degrees).

Townie Treatment Case: A Team Approach
Fig. 1
Townie Treatment Case: A Team Approach
Fig. 2
Townie Treatment Case: A Team Approach
Fig. 3
Townie Treatment Case: A Team Approach
Fig. 4


Treatment objectives

After a thorough discussion with the patient regarding our clinical analysis, we identified the following treatment objectives:

• Create a bilateral Class I dental occlusion (molar and canine).
• Correct the anterior crossbite to establish ideal anterior guidance.
• Correct the mandibular dental midline deviation.
• Correct the maxillary and mandibular deficiency to address the patient’s main aesthetic concern. • Most importantly, establish an ideal long-term functional stability.

Because the patient’s previous consultations with other practitioners had all resulted in treatment plans that recommended surgery and/ or extraction, we set out to prove that segmental mechanics using Invisalign clear aligners (Align Technology) was a viable option.

Treatment alternatives

During the in-office exam, we suggested two treatment options with the patient; for each, the discussion included advantages, disadvantages and risk analysis.

The first option was directed toward fixing the patient’s skeletal issues with a combination of orthognathic surgery and clear aligners. This option had the advantages of predictability and long-term stability, but the patient immediately declined any surgical correction.

The second option was a nonsurgical treatment plan that involved segmentalizing clear aligners in a virtual Class III (VC3) setup, Class III elastics and accelerated orthodontics using high-frequency vibration (HFV).

After the patient decided on the second option, we completed an intraoral scan using an iTero device (Align Technology) and ordered an initial 28 SmartForce/SmartTrack maxillary and mandibular aligners to be fabricated by Invisalign.

Case progress

We sectioned lower aligners distal to the lower anterior 2–2 teeth (teeth #23–#26) and added Class III buttons from the lower canines to the upper first molars (Fig. 5). Upper aligners would not be segmented.

The lower aligner, upper aligner and elastics were to be worn at least 20 hours a day. The patient was instructed to wear 3/16-inch, 6-ounce elastics for 20 hours a day for six weeks, then switch to 3/16-inch, 8-ounce elastics until it had been ascertained that Class I occlusion had established. Weekly virtual monitoring helped ensure compliance and reduce risk of “overcorrection” of occlusion.

Teeth #23–#26 were to remain stationary, while lower canine to second molar (bilateral) distalization into a full Class I occlusion was programmed. Optimized attachments on the upper and lower canines, bicuspids and first molars were added for aligner retention, and Class III cutouts for button and elastic placement were used. The upper anterior was proclined with a 1 degree-per-aligner palatal root torque, with a maximum of 10 degrees.

The patient was told to use HFV (Propel Orthodontics/Dentsply Sirona) for five minutes every night while wearing the aligners, and to switch out aligners every five days if the corrective treatment and compliance stayed on track.

To confirm case progress, each week the patient used a provided lip retractor before taking progress photos, which were uploaded to the Virtual Care platform so the treating doctor could verify the progress (Fig. 6). Because of the high level of transparency and communication with this system, the patient and doctor were able to develop a fun bonding experience that rarely exists with traditional in-office appointments.

No adverse movements or fit issues were noted during treatment. Fig. 7 shows the end-stage views of the lower arch in full Class I occlusion.

Townie Treatment Case: A Team Approach
Fig. 5
Townie Treatment Case: A Team Approach
Fig. 6
Townie Treatment Case: A Team Approach
Fig. 7


Treatment results

Orthodontic treatment was completed in 10 months—much quicker than the original estimate of 18 months.

The extraoral clinical exam at the final appointment (Fig. 8) noted the improvements in the patient’s profile: Proper lower lip setback was at normal limits, while the interincisal angle improved from the original 120 degrees to 135 degrees. The intraoral clinical exam showed ideal dental arch alignment, correction of the patient’s Class III malocclusion and alignment of his midline.

The posttreatment OPG (Fig. 9) showed proper root alignment, with no root resorption issues and no further anterior alveolar bone loss. Posttreatment cephalometric analysis (Fig. 10) showed maintenance of the sagittal relationship: SNA changed from 79.1 degrees to 79.5 degrees, SNB changed from 83.0 degrees to 82.6 degrees, and ANB changed from -3.9 degrees to -4.1 degrees.

While the maxillary incisor did not change much (U1–FH from 122.6 degrees to 121.5 degrees), the mandibular incisor was improved during treatment and correctly positioned within the mandibular symphysis. (IMPA changed from 104.3 degrees to 86.9 degrees.) The patient’s facial profile (Figs. 11–13) improved by proper repositioning of the lower lip (lower lip to E-plane 1.5 mm changed to -2.4 mm). Additionally, the FMIA (L1–FH) improved from 62.6 degrees to 77.3 degrees.

The patient was satisfied with the clinical results and expressed gratitude for achieving his beautiful new smile.
Townie Treatment Case: A Team Approach
Fig. 8
Townie Treatment Case: A Team Approach
Fig. 9
Townie Treatment Case: A Team Approach
Fig. 10

Townie Treatment Case: A Team Approach
Fig. 11
Townie Treatment Case: A Team Approach
Fig. 12
Townie Treatment Case: A Team Approach
Fig. 13

Discussion

Managing Class III malocclusions is often challenging because of skeletal/dental responses, patient compliance and patient burnout concerns. This case was successfully treated using a combination of clear aligners, Class III elastics, accelerated orthodontics using HFV, and remote monitoring.

The segmentalization of aligners for Class III malocclusions had not been well researched or published before this case was initiated. From my perspective, existing third-party “distalizers” require more office appointments, exhibit frequent breakage and unwanted reactive movements during treatment, and carry additional overhead cost. The pandemic pushed the need for an effective alternative.

Also, I have seen with Class III cases that using distal movement products can result in issues with canine extrusion/rotation and molar axial tipping/rotation from heavy use of elastics. These issues are often addressed later and fixed once the sagittal correction is completed. With VC3 mechanics using clear aligners as a tool, these unwanted “reactive” movements are minimized. Total control of first- (expansion), second- (vertical) and third- (torquing) order movements are effectively managed using Invisalign’s software.4,5

While more research is needed with VC3 cases, what is apparent is how effective segmentalizing aligners works with channeling en masse distalization. Teeth move seamlessly through the alveolar bone without resistance from the anterior teeth. Stationary placement of the lower anterior teeth helps reduce drag while the posterior teeth move distally. As with many distal movement cases, removal of wisdom teeth can be a necessary requirement.

Summary and conclusions

Using a long-established concept of sectioning aligners to generate predictable and controlled movement, complex Class III cases that often are planned with surgical correction and/or extraction of teeth can be successfully treated with clear aligners alone. This provided a benefit to this patient, who sought to avoid surgery, which was proposed in preceding consultations.

This case study also provides insight into technologies that allow for improved patient management and successful treatment for complex cases without frequent in-office visits.

References
1. Choi, SE, Simon, L, Basu, S, and Barrow, JR (2021). “Changes in Dental Utilization Patterns Due to COVID-19 Among Insured Patients in the U.S.” The Journal of the American Dental Association.
2. Bustati, N, and Rajeh, N. (2020). “The Impact of COVID-19 Pandemic on Patients Receiving Orthodontic Treatment: An Online Questionnaire Cross-Sectional Study.” Journal of the World Federation of Orthodontists, 9(4), 159–163.
3. Colonna, A, Siciliani, G, and Lombardo, L. (2021). “Orthodontic Emergencies and Perspectives During and After the COVID-19 Pandemic: The Italian Experience.” Pesquisa Brasileira em Odontopediatria e Clínica Integrada, 21.
4. Zimmo, N, Saleh, MH, Mandelaris, GA, Chan, HL, and Wang, HL. (2017). “Corticotomy-Accelerated Orthodontics: A Comprehensive Review and Update.” Compendium of Continuing Education in Dentistry (Jamesburg, N.J. : 1995), 38(1), 17–26.
5. Cai, Y. (2021). “Effectiveness of Vibration (Cyclic Loading) in Accelerating Bone Remodeling and Orthodontic Tooth Movement: A Short Review.” Journal of Mechanics in Medicine and Biology, 2140031.

Author Bio
Dr. David R. Boschken Dr. David R. Boschken graduated with a double major in biochemistry and anthropology from the University of California, Berkeley, then finished his dental degree and orthodontic training at the University of Pennsylvania School of Dental Medicine. Boschken has been treating Invisalign patients in the San Francisco Bay Area since 2000, with private practices in Los Altos and San Jose. A member of Align’s global faculty for more than 23 years, he also is a key opinion leader for Propel Orthodontics and LightForce Orthodontics.
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