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Updated: Apr 2, 2026
Author Spotlight: 3D Movement Assessment of Maxillary Posterior Teeth in Clear Aligner Treatment
Published on: February 23, 2024
Assessment of the Accuracy of Clear Aligner Therapy for Maxillary Expansion: A Prospective Clinical Study
Puja Kumari1, Rajiv Ahluwalia1, Tina Chugh1
1Department of Orthodontics and Dentofacial Orthopedics, Santosh Dental College, Santosh Deemed to be University, Ghaziabad, India.
Background:
Clear aligner therapy (CAT) is increasingly used for transverse dentoalveolar expansion of the maxillary arch; however, the extent to which digitally planned movements are clinically expressed remains uncertain.
Objective:
To evaluate the accuracy of maxillary transverse expansion achieved with clear aligners by comparing digitally predicted changes with clinically measured outcomes.
Methods:
Twelve skeletally mature adults with Class I malocclusion and maxillary constriction underwent 16 weeks of CAT. Transverse widths were recorded at pretreatment, digitally planned, and post-treatment stages using a standardized three-dimensional digital workflow with calibrated measurements on high-resolution printed models. Measurements included intercanine, inter-premolar, intermolar (mesial and distal cusp), and trans-palatal landmarks. Accuracy was calculated as the percentage of achieved relative to planned expansion. Paired-sample t-tests and repeated-measures ANOVA were performed (α = 0.05).
Results:
All transverse dimensions increased following treatment. Intercanine width increased by 1.59 mm, while first and second inter-premolar widths increased by approximately 1.21 mm. Posterior expansion was comparatively smaller, with first and second-molar widths increased by 0.7-1.0 mm. Overall accuracy ranged from 45.1% to 63.0%, indicating partial expression of digitally planned movements. Predictability was higher in the anterior and premolar regions (approximately 56-61%) than the posterior and trans-palatal sites (approximately 49-52%). Expansion remained symmetrical, with no significant right-left differences in buccolingual inclination. No clinically detectable adverse effects were observed during the study period. Males demonstrated slightly greater second-molar transverse dimensions (p<0.05).
Conclusion:
Clear aligner therapy produced measurable and symmetrical dentoalveolar maxillary expansion in skeletally mature adults, however the magnitude of transverse change was consistently lower than digitally planned values. Predictability decreased posteriorly, suggesting that calibrated digital overcorrection may improve alignment between virtual planning and clinical expression.
