Sagittal split osteotomy with or without third molar removal: A prospective cohort study on inferior alveolar nerve disturbances

Résumé

Objective: The aim of this study is to evaluate whether the simultaneous removal of mandibular third molars during sagittal split osteotomy (SSO) influences the incidence and severity of postoperative neurosensory disturbances of the inferior alveolar nerve (IAN).Material and methods: In this prospective cohort study, 172 SSO procedures were analyzed at the Department of Oral and Maxillofacial Surgery, AZ VitazHospital, Belgium. Patients were divided into two groups: those with no third molars present (Group I, n = 117) and those undergoing simultaneous third molar removal during SSO (Group II, n = 55). Neurosensory function was evaluated at 1 day, 1 week, 3 weeks and 6 weeks postoperatively using objective (Medical Research Counsel (MRC) scale, two-point discrimination, static light touch, sharp/blunt discrimination) and subjective measures. Logistic regression and ANCOVA were used to assess associations between third molar status and neurosensory outcomes. Results: In both groups, high sensory recovery rates were achieved six weeks after surgery: 91% and 95%, respectively. There were no statistically significant differences between the groups in terms of the duration required to reach functional sensory recovery (p = .650), final MRC score distribution (p = .702), two-point discrimination scores, or static light touch or sharp/blunt discrimination. Entrapment of the IAN occurred more frequently in patients with third molars (69.1% vs. 53.8%), but this difference was not statistically significant (p = 0.058). Entrapment and patient age were significant predictors of neurosensory complaints. No adverse outcomes occurred in either group. Conclusions: Simultaneously removing mandibular third molars during SSO does not significantly impact postoperative neurosensory outcomes. Age and inferior alveolar nerve (IAN) entrapment are more critical risk factors for altered sensation. These findings support the safety of removing third molars at the same time as orthognathic surgery.