Coronectomy of mandibular third molars: a clinical and radiological study of 231 cases with a mean follow-up period of 5.7years.

Coronectomy is a widely accepted treatment for mandibular third molars that are in close relationship to the mandibular canal. However, long-term studies on morbidity following this procedure have not been presented. The aim of this study was to examine the long-term morbidity after coronectomy, with sensory disturbances of the inferior alveolar nerve (IAN) and root migration as the primary outcome variables. A total of 231 mandibular third molar coronectomies were performed in 191 patients with a mean follow-up period of 5.7years (range 1-12years). The prevalence of IAN injury was 1.3%, and 3.5% of the retained roots were removed. None of the reoperations to remove the retained roots caused IAN impairment. Infections occurred in 11.7% of the cases and all were treated with antibiotics. Overall, 97% of the retained roots showed signs of migration and 65% showed signs of rotation. Therefore, coronectomy of the mandibular third molars with an intimate relationship to the mandibular canal seems to be a safe treatment modality with a good long-term prognosis.