Effects of surgical mandibular advancement and rotation on signs and symptoms of temporomandibular disorder: A 2-year follow-up study

Introduction: The possible effects of orthognathic surgery on signs and symptoms of temporomandibular disorder (TMD) are still controversial. We prospectively investigated the association between the amount of advancement and rotation of the mandible during bilateral sagittal split osteotomy (BSSO) and the development of TMD signs and symptoms. Methods: Class II patients (n = 127) received mandibular advancement with BSSO. We used factorial analysis of covariance to assess whether the magnitude (< or ≥7 mm) and the direction (clockwise or counterclockwise) of the movement were associated with the onset or worsening of TMD signs and symptoms during 2 years of follow-up. Results: Counterclockwise rotation of the mandible was associated with more muscle tenderness, especially in patients receiving long advancements. The combination of long advancement with counterclockwise rotation was also associated with increased joint symptoms. All symptoms declined over the 2-year follow-up period. Conclusions: Counterclockwise rotation of the mandible is related to a slight increase in muscle symptoms after BSSO. The combination of counterclockwise rotation with long advancement also might increase joint signs and symptoms. All symptomatology tended to decline over time, suggesting that the amount of advancement and mandibular rotation should not be considered as risk factors for the development of TMD in patients without preexisting conditions.