Three-Dimensional Assessment of Collum Angle in Different Sagittal Malocclusions: A Cross-Sectional Study

Assessment of crown-root angulation of the anterior teeth as defined by the collum angle (CA) is crucial for diagnosis and treatment planning. This study was undertaken to evaluate the CA of all anterior teeth within both the maxillary and mandibular arches across various sagittal malocclusions using cone-beam computed tomography (CBCT). Additionally, the secondary aims included investigating sex disparities and side variances in this angular measurement.

This cross-sectional study was conducted on 80 pre-orthodontic patients divided into four groups with 20 patients in each group: Group 1, dentoskeletal class I; Group 2, dentoskeletal class II with division 1 malocclusion; Group 3, dentoskeletal class II with division 2 malocclusion; and Group 4, dentoskeletal class III malocclusion. CA was assessed using CBCT for all anterior teeth in both jaws. The data were then subjected to statistical analysis.

There were statistically significant differences in the CA for all anterior teeth in both jaws among all groups (p<0.05). The mean CA was highest in Group 3, followed by Groups 4, 2, and 1 for the maxillary central incisors (CIs). The mean CA was highest in Group 3, followed by Group 2, Group 1, and Group 3 for the maxillary lateral incisors (LI). The mean CA was highest in Group 3, followed by Groups 2, 4, and 1 for the maxillary canines. The mean CA was highest in Group 3, followed by Groups 4, 2, and 1 for the mandibular CI. The mean CA was highest in Group 3, followed by Groups 4, 2, and 1 for the mandibular LI. The mean CA was highest in Group 3, followed by Groups 4, 2, and 1 for the mandibular canines. There were no statistically significant sex or side (right and left) differences between the groups (p>0.05).

The highest CA was observed in class II division 2 for all the anterior teeth. The CA of the mandibular teeth was lower than that of the maxillary teeth, and the lowest values of CA were obtained for mandibular teeth in class I malocclusion.