Tooth movement analysis during expansion
Date
2025-06-13
Journal Title
Journal ISSN
Volume Title
Publisher
Universidad CES
Abstract
Objective: The aim of this study was to estimate the necessary activation parameters (force application point and magnitude) to achieve bodily dentoalveolar expansion of maxillary posterior teeth by simulating the interaction of clear aligners, teeth, and attachments in a finite element model. Materials and methods: a CBCT file from a female patient in early adulthood with permanent dentition, exhibiting a Class III malocclusion with transverse maxillary deficiency was segmented to obtain maxillary bone and upper dentition followed with Boolean operations to create periodontal ligament, aligner and attachments where modeled, all structures where simplified and elements were created to then simulate bodily displacements of maxillary posterior teeth using basic trigonometric formulas, all using open-source software. Results: Anterior teeth showed controlled labial tipping with incisal intrusion. The premolars showed predominant mesialization and right molars distalization, questioning truly bodily expansion. The left molars showed no significant displacement.
In general, the posterior region had a predominantly anteroposterior displacement with slight changes in the transverse axis and no changes along the vertical. Conclusions: Achieving predictable dentoalveolar expansion with clear aligners is a complex biomechanical challenge influenced by individual tooth orientation, patient asymmetries, and the interaction of applied forces. Accurate prediction needs determining specific force systems for each tooth to control the moment-to-force ratio and account for potential multi-planar movements beyond simple buccal tipping, as demonstrated by the occurrence of rotations, inclinations, and tipping in this 3D analysis. These results highlight that we need more detailed planning that consider how each tooth is positioned and what makes each patient different to improve clear aligner expansion.
Description
Keywords
Expansion, FEM, Force, Displacement, Predictability