Evaluating the impact of attachment designs on canine derotation in clear aligner therapy: A finite element analysis

Introduction: Canine derotation is one of the most technique-sensitive movements in clear aligner therapy (CAT), and its predictability depends largely on attachment geometry. This study investigates the biomechanical influence of various attachment designs using finite element analysis (FEA). Methods: A 3D finite element model of the maxillary arch was developed to simulate canine rotation. Three attachment designs were tested: vertical-angulated labial attachments (VL), labial and palatal attachments (VLP), and labial attachments with palatal pressure points (VLPPP). Rotational forces of 10°–40° were applied, and tooth displacement, attachment deformation, and stress distribution in the periodontal ligament (PDL) and alveolar bone were analyzed using ANSYS simulation software. Results: The VLPPP design generated the greatest tooth displacement (0.017 mm) but also exhibited the highest PDL and bone stress (516.10 MPa). The VL design produced minimal displacement (0.012 mm) and lowest stress (374.33 MPa). The VLP configuration achieved an optimal balance between movement and biological safety. Conclusions: Multi-surface force application, as seen in the VLP design, enhances biomechanical control and minimizes stress in canine derotation using CAT. FEA validates these attachment configurations for improved clinical outcomes.