Mandibular Asymmetry in Patients with Skeletal Class I and Skeletal Class II Malocclusions: A Cone-beam Computed Tomography Study.

OBJECTIVE: To study the difference in mandibular asymmetry between patients with skeletal Class I and skeletal Class II malocclusions and analyze the correlation between mandibular asymmetry and different facial skeletal sagittal patterns based on CBCT measurements.

METHODS: One hundred and twenty patients were selected according to the inclusion and exclusion criteria. Patients were divided into two groups (60 in the skeletal Class I group and 60 in the skeletal Class II group) based on ANB angles and Wits values. Patients' CBCT data were collected. Dolphin Imaging 11.0 was used to determine the mandibular anatomic landmarks and calculate the linear distance in patients in the two groups.

RESULTS: Intragroup comparison: in skeletal Class I group, measurements of the most posterior point of the condyle (Cdpost), the outer lateral point of the condyle (Cdlat), sigmoid notch point (Sn)), coronoid process point (Cop), gonion point (GO) and antimony notch point (Ag), right>left (P<0.05); in skeletal Class II group, measurements of Cdpost and Cop, right>left (P<0.05). Intergroup comparison: for measurements of GO and Ag, skeletal Class I group>skeletal Class II group (P<0.05). The asymmetry of the Ag and GO points was negatively correlated with the ANB angle (p<0.05).

CONCLUSION: Mandibular asymmetry was significantly different between patients with skeletal Class I and skeletal Class II malocclusions. The asymmetry of the mandible angle region in the former group was greater than that in the latter group, and the asymmetry of the mandibular angle was negatively correlated with the ANB angle.