Concomitant removal of mandibular third molars during sagittal split osteotomy minimizes neurosensory dysfunction.

PURPOSE: Inferior alveolar nerve (IAN) injury is 1 of the most important postoperative complications after sagittal split osteotomy (SSO). The purpose of our study was to investigate the effects of the presence or absence of a mandibular third molar on the neurosensory recovery of the IAN after SSO.

MATERIALS AND METHODS: A prospective cohort study enrolled a sample composed of patients who underwent SSO to correct mandibular deformities. The primary predictor variable was the status of the mandibular third molar at the time of SSO and it was divided into two levels, present at the time of SSO (Group I) or absent at the time of SSO (Group II). The primary outcome variable was neurosensory recovery of the IAN, assessed using the Medical Research Council scale, functional sensory recovery, and subjective evaluation. Neurosensory status was measured 3 times (preoperatively and 3 and 6 months postoperatively). Appropriate bivariate and multivariate statistics were computed, and the level of statistical significance was set at P < .05.

RESULTS: A total of 120 SSOs were performed in 60 patients. Group I included 64 SSOs (mean patient age ± SD 19.3 ± 8.0 years) and group II, 56 SSOs (mean patient age 24.9 ± 10.0 years). The Medical Research Council scale scores showed that the presence of third molars during SSO was associated with a statistically significant decreased incidence of neurosensory disturbance of the IAN at 3 and 6 months postoperatively (all P < .01). Functional sensory recovery was achieved more frequently in group I, but this difference remained significant only at 3 months after adjusting (P = .01). A "normal sensation" was subjectively reported more frequently in group I at 3 and 6 months postoperatively (P ≤ .05).

CONCLUSIONS: The presence of third molars during SSO minimizes postoperative neurosensory disturbance of the IAN.