Coronectomy: A Surgical Option for Impacted Third Molars in Close Proximity to the Inferior Alveolar Nerve—A 5-Year Follow-Up Study

Purpose: The extraction of third molars is the most common surgical procedure performed in the oral cavity. Coronectomy is a surgical protocol to reduce the risk of neurologic lesions to the inferior alveolar nerve (IAN). We evaluated early (up to 1 month) and late (from 2 to 60 months) postoperative complications. Materials and Methods: This prospective cohort study enrolled patients treated at the Unit of Oral and Maxillofacial Surgery, University of Bologna. The predictor variable was the time after coronectomy with up to 5 years' follow-up. To assess the rate of postoperative complications, the outcome variables were neurologic injuries, postoperative pain, swelling, fever, alveolitis, pulpitis, and root exposure. The success rate, need for a second surgical procedure, probing pocket depth, and bleeding on probing also were investigated. Univariate and bivariate descriptive statistics, Kaplan-Meier analysis, and Cox hazards modeling were performed to evaluate the variables. Results: We performed 116 coronectomies in 94 healthy patients (37 men and 57 women; mean age, 28.99 ± 8.9 years). At 5 years' follow-up, we re-evaluated 63 patients with 76 coronectomies. In total, 30 complications were verified. No cases of neurologic lesions to the IAN or lingual nerve were observed after surgery. In the first 3 years, the surgeons extracted migrated roots in 5 cases (6%) without any neurologic lesions to the IAN. No complications were observed from the third to fifth year. Conclusions: This prospective study on coronectomy of third molars in a close relationship with the mandibular canal found no cases of neurologic lesions, no cases of late infection of the retained roots at 5 years, and a low rate of immediate postoperative complications. Further investigations should include a follow-up study at 10 years and more research about the mechanism of pulp healing.