Biomechanical evaluation of attachment geometries for labio-lingual inclinations in maxillary incisors of class II division 2 malocclusion: A 3D finite element analysis

Introduction: Class II Division 2 malocclusion requires precise torque control due to retroclined maxillary incisors. This study evaluates the biomechanical efficiency of attachment designs in clear aligner therapy using 3D finite element analysis (FEA). Methods: A digital FEM model of the maxilla was reconstructed from CBCT data. Three attachment geometries—labial horizontal attachments (LHA), palatal horizontal attachments with labial power ridges (PHALPR), and labial-palatal reciprocal power ridges (LPRPR)—were analyzed under controlled torque simulations. Results: LPRPR showed the greatest displacement (0.1418 mm) and stress (384.89 MPa), followed by PHALPR and LHA. Lateral incisors exhibited higher stress concentrations than central incisors. Conclusions: Attachment geometry significantly influences torque expression in aligner therapy. The LPRPR design provided superior control, offering enhanced biomechanical performance in Class II Division 2 cases.