Does maxillary yaw exist in patients with skeletal Class III facial asymmetry?

Introduction: This study aimed to evaluate maxillary skeletal and dental yaw in patients with skeletal Class III facial asymmetry and investigate its correlation with menton deviation. Methods: Initial cone-beam computed tomography data from 60 patients with skeletal Class III malocclusion were used. There were 30 patients in both the symmetrical group (menton deviation <2 mm) and the asymmetrical group (menton deviation >4 mm). After reconstruction of 3-dimensional (3D) cone-beam computed tomography data, maxillary yaw and 3D positions of skeletal and dental landmarks were measured and compared between the groups. After that, correlations between menton deviation and the other variables were assessed. Results: No significant difference was noted in maxillary skeletal and dental yaw between the 2 groups. In the assessment of 3D positions, translation of the maxillary bone and maxillary dentition toward the menton deviation was observed (P <0.01). Maxillary skeletal and dental yaw was not significantly correlated with menton deviation in the asymmetrical group. Conclusions: Maxillary skeletal and dental yaw was not evident in either group. Therefore, when planning maxillary surgery for patients with skeletal Class III facial asymmetry malocclusion, it may be appropriate to shift the focus of decompensation from maxillary yaw to maxillary translation.