Does the application of counter-clockwise rotation in mandibular advancement increase the stress on the inferior alveolar nerve?

Sagittal split ramus osteotomy (SSRO) is a reliable surgical procedure for the correction of maxillofacial deformities. However, the most common complication that occurs after the procedure is a neurosensorial disturbance of the inferior alveolar nerve (IAN). Especially in individuals with retrognathic mandible or sleep apnoea, it may be necessary to perform a large amount of mandibular advancement and counter-clockwise (CCW) rotation depending on the angle of the mandibular plane. The likelihood of prolonged neurosensorial disturbance is increased in such patients. The objective of this experimental study was to evaluate the accumulation of stress on the IAN caused by different amounts of advancement and CCW rotation using finite element analysis. The mandibular models with SSRO were advanced 6, 9, and 12 mm and rotated 10 degrees CCW. According to the data obtained, a slight increase in stress values was observed when 10 degrees CCW rotation was applied. However, it was found that significant increases in stress values were directly proportional to the amount of advancement. This experimental study showed that the main cause of stresses on the inferior alveolar nerve after SSRO is the amount of advancement rather than the amount of CCW rotation.