Anterior Tooth Inclination Between Skeletal Class II and III Malocclusions After Surgical Orthodontic Treatment

Background/Objectives: Anterior tooth inclination plays a critical role in treatment planning for surgical orthodontic cases. However, post-treatment outcomes in patients with jaw deformities often deviate from cephalometric values. This study aimed to compare anterior tooth inclination and skeletal morphology among patients with Class II and Class III malocclusions and to establish reference values for individualized treatment plans. Methods: A total of 122 patients (Class II: n = 40; Class III: n = 41; Class I: n = 41 as a control) were retrospectively analyzed. Cephalometric parameters, including U1 to FH and L1 to MP, were measured pre- and post-treatment. Group differences were analyzed using one-way ANOVA and Tukey's multiple comparison test. Multiple regression analysis was used to establish prediction models for anterior tooth inclination. The threshold for statistical significance was set at p < 0.05. Results: Post-treatment, upper anterior teeth were more lingually inclined in Class II patients and more labially inclined in Class III patients compared to Class I controls (U1 to FH: Class II, 106.8°; Class III, 120.4°; Class I, 111.1°; p < 0.01). Lower anterior teeth were more lingually inclined in Class III patients compared to Class I patients (L1 to MP: 84.9°; p < 0.01). Regression models demonstrated good predictive value (R² > 0.5) in non-extraction cases. Conclusions: Regression equations developed in this study, alongside the cephalometric averages of Class I individuals, may offer reliable reference values tailored to individual craniofacial morphology, contributing to optimized treatment planning in surgical orthodontic cases.