Incidence of osteoradionecrosis of the jaws: a retrospective study of 620 patients with head and neck cancer.

This study aimed to assess systemic and local risk factors for the development of osteoradionecrosis (ORN) of the jaws and its incidence in patients with head and neck cancer undergoing radiotherapy (RT). This was a retrospective cohort study of 620 adults following irradiation for head and neck cancer in 2011 or 2012. Among 181 patients who did not require any tooth extractions, the incidence of ORN was 0.5%. Among 266 patients with a total of 1491 tooth extractions (mean, 5.5 teeth per patient) performed before RT, the incidence of ORN was 3.7%. In all cases, ORN was observed in extraction sites located in the field of radiation. No extractions were performed during RT. Fifteen patients underwent extractions both before and after RT. Of the 53 tooth extractions performed after RT (20 patients; mean, 2.7 teeth per patient), 15 were in the field of radiation. No case of ORN was reported in that group. Among 168 edentulous patients, the incidence of ORN was 1.8%. Within the limitations of this study, the results suggest that the incidence of ORN can be minimized with a meticulous pre-RT dental examination, a comprehensive treatment plan, and diligent post-RT follow-up examinations conducted by an experienced multidisciplinary team.