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.

The presence of mandibular third molars during sagittal split osteotomies does not increase the risk of complications.

PURPOSE: The purpose of this study was to investigate prospectively the effects of the presence or absence of third molars during sagittal split osteotomies (SSOs) on the frequency of unfavorable fractures, degree of entrapment and manipulation of the inferior alveolar nerve (IAN), and procedural time. MATERIALS AND METHODS: The investigators designed and implemented a prospective cohort study and enrolled a sample composed of patients who underwent SSOs 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 2 levels, present at the time of SSO (group I) or absent at the time of SSO (group II). The primary outcome variable was unfavorable splits. The secondary outcome variables were the degree of entrapment/manipulation of the IAN and the procedural time. Appropriate bivariate and multivariate statistics were computed, and the level of statistical significance was set at P < .05. RESULTS: Six hundred seventy-seven SSOs were performed in 339 patients: group I consisted of 331 SSOs (mean age ± SD: 19.6 ± 7.4 yrs), and group II consisted of 346 SSOs (30.4 ± 12.1 yrs). The overall rate of unfavorable fractures was 3.1% (21 of 677), with frequencies of 2.4% (8 of 331) in group I, compared with 3.8% (13 of 346) in group II (P = .3). The rate of IAN entrapment in the proximal segment was significantly lower in group I (37.2%) than in group II (46.5%; P = .01). The degree of entrapment was also significantly more severe for group II (P < .001). Third molars increased procedural time by 1.7 minutes (P < .001). CONCLUSIONS: The presence of third molars during SSOs is not associated with an increased frequency of unfavorable fractures. Concomitant third molar removal in SSOs also decreases proximal segment IAN entrapment but only slightly increases operating time.