OSTEORADIONECROSIS

Osteoradionecrosis (ORN) is a condition of nonvital bone in a site of radiation injury. ORN can be spontaneous, but it most commonly results from tissue injury. The absence of reserve reparative capacity is a result of the prior radiation injury. Even apparently innocuous forms of trauma such as denture-related injury, ulcers, or tooth extraction can overwhelm the reparative capacity of the radiation-injured bone. Traditionally, 3 grades of disease (I, II, III) are recognized. Grade I ORN is the most common presentation. Exposed alveolar bone is observed. Grade II designates ORN that does not respond to hyperbaric oxygen (HBO) therapy and requires sequestrectomy/saucerization. Grade III is demonstrated by full-thickness involvement and/or pathologic fracture. Therefore, patients can demonstrate grade I or grade III ORN at initial presentation.