Osteoradionecrosis, pathogenesis, treatment and prevention.

The present paper discuss the development of osteoradionecrosis (ORN) in the jaws. ORN is the end stage of tissue injury induced by irradiation. The most prominent etiologic factor of ORN seems to be the effect of radiation on endothelial cells lining the vessels. These cells are, as tumor cells, highly radiosensitive, and radiation leads to a vascular damage resulting in hypoxic, hypovascular and hypocellular tissues. Wound healing in such tissues is impaired since nutritional demands of the wound, including oxygen, cannot be supplied due to the degenerative changes in the blood vessels. The paper furthermore describes the scientific basis for the use of hyperbaric oxygen therapy (HBO) in ORN. HBO increase the vascularity in the tissues injured by radiation, and thus tissue viability and healing capacity is increased reducing the risk for spontaneous or traumainduced ORN. Protocols for the treatment of patients with ORN are presented and prophylactic guidelines are described.