Comparative evaluation of composite attachment sizes for bodily movement of upper canine with removable thermoplastic aligner system: A finite element analysis

Introduction: Clear aligners are popular for their aesthetics and comfort, but achieving complex tooth movements like canine translation remains challenging.Composite attachments improve aligner retention and force transmission, with their design impacting movement efficiency and stress distribution.This study uses finite element analysis (FEA) to compare rectangular and semicircular attachments in facilitating upper canine bodily movement, analyzing displacement patterns and stress concentrations.Objective: This study aimed to compare the biomechanical efficacy for bodily movement canine of two composite attachment designs-large rectangular and two small semicircular-for bodily movement of the upper canine using removable thermoplastic aligners through finite element analysis (FEA).Materials add Methods: A 3D finite element model of the maxillary arch, including teeth, periodontal ligament (PDL), and alveolar bone, was constructed from CBCT data.Two attachment configurations were simulated: (1) a single large rectangular attachment and (2) two small semicircular attachments.Displacement patterns and stress distribution were analyzed under identical force conditions.Results: The rectangular attachment produced greater crown displacement (0.0137 mm vs. 0.0100 mm).The semicircular attachments demonstrated more uniform stress distribution and a smaller crown-root displacement differential (0.0047 mm vs. 0.0064 mm), suggesting improved bodily movement.Conclusion: Semicircular attachments may offer superior clinical performance by reducing stress concentrations and promoting controlled tooth movement.These findings advocate for attachment design optimization in aligner therapy to enhance biomechanical efficiency.