Effects of the Mandibular Functional Units and Soft Tissue on Facial Asymmetry

Mandibular asymmetry has a variety of patterns because they are affected the position and the shape of mandible in addition to the overlying soft tissue. This study aimed to assess the factor in mandibular asymmetry, focusing on each mandibular functional units and the soft tissue thickness in the mandibular angle area. Forty patients who were diagnosed with facial asymmetry and undergone the orthognathic surgery without genioplasty were enrolled in this study. The skeletal patterns of the patients were analyzed by using cone-beam computed tomography data and 3D virtual images divided into 2 categories; the mandibular functional unit length and the soft tissue depth. All difference in bilateral mandibular functional unit lengths had a statistically significant with chin top deviation (P<0.05). The greatest correlation was the condylar unit length compared with other functional units. The soft tissue thickness in the mandibular angle area was not statistically related to chin top deviation (P>0.05), and the soft tissue did not change remarkably after orthognathic surgery (P>0.05). This study suggests that the considerations of a surgical plan for treatment based on the mandibular asymmetry.