Assessment of chin morphology in different skeletal dysplasia - A cross-sectional study

The objective of the study is to evaluate the morphology of the symphyseal region of adult skeletal Class II and Class III malocclusion as compared with Skeletal Class I subjects.

The symphyseal width and height were evaluated using data from 80 lateral cephalograms of the age range of 18 years to 25 years. Average growing Skeletal Class II (n = 30) and Class III (n = 20) subjects were used as a comparison group. Average growing normal occlusion samples (n = 30) were used as controls.

Alveolar height was similar in all groups. The width of the symphyseal region including basal width, the width of the cervical region of the lower central incisor at the cementoenamel junction, and symphysis width were found to be similar in all groups. There is no significant difference in gonial angle in both Class II and III groups as compared to control. Articular angle showed no significant difference. Mandibular incisor dentoalveolar height (L1-AH) was found to be significantly higher in the Class II group (P < 0.05).

There are no definite morphological differences in the symphyseal region between average grower Class I, Class II, and Class III skeletal malocclusions except mandibular incisor dentoalveolar height (L1-AH) and incisor mandibular plane angle which is higher whereas ramus length and body length which is lesser in Class II group as compared with controls. Width of the cervical region of the lower central incisor at the cementoenamel junction (Id-Id') and incisor mandibular plane angle was lower than control in Class III subjects.