Collum angle of mandibular central incisors across different sagittal skeletal malocclusions: a cross-sectional study

Purpose To evaluate the collum angle (CA) of mandibular central incisors among different skeletal malocclusions (Class I, Class II Division 1, Class II Division 2, and Class III) and to assess sex-related differences.Materials and methods This cross-sectional study analysed 100 lateral cephalograms (25 per group) of patients aged 18–50 years. The CA was measured as the angle between the long axis of the crown and root of the mandibular central incisor. Intra-observer reliability was excellent (ICC = 0.99). Data were analysed using SPSS v23. Intergroup differences were evaluated with the Kruskal – Wallis test, and sex differences with the Mann–Whitney U test. ANCOVA was performed to adjust for age and gender effects. A p-value < 0.05 was considered statistically significant.Results The mean CA was highest in Class II Division 2 and lowest in Class III, though differences among groups were not statistically significant (p > 0.05). Males showed slightly higher CA values (mean difference = 0.25°), but this difference was not significant. ANCOVA confirmed no significant influence of age or gender, and no interaction between skeletal pattern and gender (p > 0.05).Conclusion No statistically significant differences in mandibular incisor CA were observed among Class I, Class II Division 1, Class II Division 2, and Class III skeletal malocclusions. Although some differences were noted, they were not enough to establish a consistent relationship with different types of skeletal malocclusion and CA.