What Are the Types and Frequencies of Complications Associated With Mandibular Third Molar Coronectomy? A Follow-Up Study

PURPOSE: Coronectomy has been proposed for impacted third molars in close proximity to the inferior alveolar nerve (IAN) to avoid neurologic injury. Immediate (up to 1 month) and late (2 to 36 months) postoperative complications were investigated. MATERIALS AND METHODS: A prospective cohort study was performed on healthy patients treated in the dental clinic of the Department of Oral Surgery, University of Bologna. The predictor variables examined were experience of the surgeon (<10 vs ≥10 yr), length of surgery, type of mandibular third molar inclusion, and patient age. To assess the rate of postoperative complications, outcome variables were neurologic injuries, postoperative pain, swelling, fever, alveolitis, pulpitis, and root exposure. The success rate and need for a second surgery also were investigated. Univariate and bivariate descriptive statistics, Kaplan-Meier analysis, and Cox hazards modeling were performed to evaluate the variables. RESULTS: The study involved 94 healthy patients (mean age, 28.99 ± 8.9 yr; range, 17 to 56 yr; 37 men and 57 women) who had 116 third mandibular molars treated with coronectomy. During the 3-year follow-up period, 28 patients (29 coronectomy procedures) dropped out of the study. There was no case of neurologic injury to the inferior alveolar nerve (IAN) or to the lingual nerve (LN). In total, 30 complications were observed (25 within 1 month; 5 at 2 to 12 months). Surgeons with less than 10 years of training exposed patients to a greater risk of complications (hazard ratio = 2.069; 95% confidence interval, 1.004-4.263). An overall success rate of 74% at 6 months was estimated, and a second surgery was needed in 6% of cases. Of the retained roots analyzed, 80% showed postoperative root migration. CONCLUSIONS: In this study, coronectomy of mandibular third molars did not result in temporary or permanent injury to the IAN or LN. Coronectomy showed a low rate of postoperative complications. However, within the first year, a second surgery was needed in 6% of coronectomy procedures to remove migrated root fragments. Additional studies with larger patient samples are recommended to further investigate differences in postoperative complications in relation to patient age.coro