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Author Spotlight: 3D Movement Assessment of Maxillary Posterior Teeth in Clear Aligner Treatment
Published on: February 23, 2024
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How accurate is predicted root movement achieved in four first-premolar extraction cases with Invisalign?
Fanfan Dai1,2, Yanhui Sang1,2, Jingjing Zeng1,2
1Second Clinical Division, Peking University School and Hospital of Stomatology, Beijing, China.
Orthodontics & Craniofacial Research
|August 13, 2024
Summary
Invisalign treatment with four first-premolar extractions showed significant differences between predicted and achieved root movements, especially for anterior teeth. Actual root movements in the anteroposterior direction were poorly achieved compared to predictions.
Area of Science:
- Orthodontics
- Dental Technology
- Biomechanical Engineering
Background:
- Predicting and achieving precise root movement is crucial in orthodontic treatment planning.
- Four first-premolar extractions are a common strategy for managing dental crowding and protrusion.
- Invisalign, a popular clear aligner system, offers an alternative to traditional braces.
Purpose of the Study:
- To compare the predicted versus achieved root movements in adult patients undergoing Invisalign treatment after four first-premolar extractions.
- To evaluate the accuracy of root apex positioning in Invisalign therapy within this specific clinical scenario.
Main Methods:
- Retrospective analysis of 33 adult patients treated with Invisalign after four first-premolar extractions.
- Registration of pretreatment cone-beam computed tomography (CBCT) models with surface-scanned dental models (SSDM) to establish initial root apex positions.
- Comparison of predicted and achieved post-treatment root apex positions using CBCT and SSDM data.
Main Results:
- Anteroposterior root movements of maxillary and mandibular anterior teeth were significantly underestimated (3.24–5.74 mm DPARMs, p < .05).
- Vertical root movements showed greater intrusion than predicted for maxillary anterior teeth (0.70–0.93 mm DPARMs, p < .05) but less for mandibular incisors (0.57–0.65 mm DPARMs, p < .05).
- Mediolateral root movements deviated from predictions, with lateral incisors not moving distally and canines not moving buccally as expected.
Conclusions:
- Invisalign treatment involving four first-premolar extractions does not consistently achieve predicted root movements.
- Significant discrepancies exist between planned and actual root apex positions, particularly in the anteroposterior dimension for anterior teeth.
- The findings highlight potential limitations in predicting and controlling complex root movements with clear aligners in extraction cases.
