Risk factors for jaw osteoradionecrosis: a case control study.

There are divergences among studies regarding features associated to increased risk of osteoradionecrosis (ORN). Our objective was to identify factors that predispose to the development of ORN of the jaw. This was a retrospective, hospital-based, case-control study involving patients with head and neck cancer who had been treated with ≥ 60 Gy external radiotherapy (RT) to the jaw. A total of 19 cases of ORN and 43 controls were included. The patients' demographic data, tumor type, staging, treatment and outcome information, and pre-treatment oral status were collected. Univariate analysis showed that the oral cavity/oropharynx sites were associated with 9.77-fold increased risk of ORN development compared to other sites (p = 0.005). Being an active smoker was associated with 3.95-fold increased risk of ORN development (p = 0.01). A tendency towards increased risk of ORN was observed particularly when tooth extraction occurred after RT (odds ratio (OR): 3.04; p = 0.08). Multivariable analysis showed that tumor site was the only significant risk factor (OR: 21.03, p = 0.01). The oral and oropharyngeal primary site is an important risk factor for ORN. Dental extraction, which did not occur in 28% of the sample, was not an essential event for ORN development.