What is "osteoradionecrosis"

Osteoradionecrosis is a possible complication following radiotherapy where an area of bone does not heal from irradiation. Irradiation of bones causes damage to osteocytes and impairs the blood supply. The affected hard tissues become hypovascular (reduced number of blood vessels), hypocellular (reduced number of cells) and hypoxic (low levels of oxygen). Osteoradionecrosis usually occurs in the mandible, and causes chronic pain and surface ulceration. Prevention of osteradionecrosis is part of the reason all teeth of questionable prognosis are removed before the start of a course of radiotherapy.