Comparative Study Of Aligners Versus Fixed Appliances In Bimaxillary Protrusion

This study conducted a comparative analysis by measuring three-dimensionally superimposed digital dental models, evaluating the therapeutic efficacy of clear aligners versus fixed appliances in treating maxillary anterior teeth for bimaxillary protrusion patients requiring premolar extraction. This retrospective study included 38 patients requiring extraction of four first premolars for bimaxillary protrusion. Displacement and angular changes of the maxillary central incisors, lateral incisors, and canines were measured using pre- and post-treatment cone-beam computed tomography (CBCT) scans and intraoral scan data. Compared to fixed appliances, clear aligners demonstrated significantly greater vertical intrusion of canines (P < 0.001), increased buccal movement of canines in the coronal plane (P < 0.001), and less distal movement of canines in the sagittal plane (P < 0.01). No statistically significant difference was observed in the rotational changes of maxillary anterior teeth between the two appliance systems. However, significant differences were identified in axial inclination changes for central incisors (P < 0.05), lateral incisors (P < 0.001), and canines (P < 0.001). Notably, central incisors treated with clear aligners exhibited more lingual inclination compared to those treated with fixed appliances (P < 0.05). In the treatment of bimaxillary protrusion in adult patients, clear aligners can achieve multidimensional movement of maxillary anterior teeth; however, they exhibit weaker biomechanical efficiency compared to fixed appliances, particularly in controlling central incisor torque and anterior tooth axial inclination. This necessitates the incorporation of overcorrection design strategies to optimize treatment outcomes.