Objective: To evaluate and compare mandibular incisor inclination and alveolar bone thickness among subjects with Angle's Class I, Class II Division 1, and Class II Division 2 malocclusions using cone-beam computed tomography (CBCT)

Materials and Methods: Forty-two untreated subjects aged 16–25 years were equally divided into three groups: Class I, Class II Division 1, and Class II Division 2 malocclusions (n=14 each). CBCT images were obtained using the Carestream 9000 3D imaging system. Mandibular incisor inclination was assessed using the Incisor Mandibular Plane Angle (IMPA). Alveolar bone thickness around the mandibular right central incisor was measured at eight sites. Intergroup comparisons were performed using one-way ANOVA and Tukey post hoc tests. Pearson correlation analysis was used to evaluate the relationship between IMPA and alveolar bone thickness.

Results: The mean IMPA differed significantly among the three groups (p<0.001). Class II Division 1 subjects exhibited the highest IMPA (105.21 ± 4.49°), whereas Class II Division 2 subjects demonstrated the lowest IMPA (88.85 ± 6.57°). Significant intergroup differences in alveolar bone thickness were observed at B1B2 (p=0.004) and C1C2 (p<0.001). Significant negative correlations between IMPA and A1A2 thickness were observed in Class I (r=-0.589, p=0.027) and Class II Division 2 subjects (r=-0.534, p=0.049). Class II Division 2 subjects also demonstrated a significant negative correlation between IMPA and E1E2 thickness (r=-0.701, p=0.005).