OSTEORADIONECROSIS OF THE JAWS - A RETROSPECTIVE STUDY OF THE BACKGROUND FACTORS AND TREATMENT IN 104 CASES

Purpose: This study analyzed potential risk factors in patients who re ceived radiation therapy and then developed osteoradionecrosis (ORN). Patients and Methods: A group of 104 patients who developed osteoradio necrosis of the jaws were reviewed treated between 1972 and 1992. Resu lts: The most common affected site was the mandible (99 cases, 95.2%), followed by the maxilla (5 cases, 4.8%), Among all cases, 93 (89.4%) were induced-trauma ORN, and 11 (10.6%) were spontaneous ORN, The foll owing risk factors were considered as predisposing factors for the app earance of ORN, Anatomic location of the tumor, tumor surgery, total r adiation dose, dose rate/day, mode of radiation delivery, time from ra diation therapy until the onset of ORN, and dental status, ORN develop ed more frequently with oral cancer than other head and neck cancers, The size of the tumor seemed not to influence the incidence of ORN exc ept when the tumor invade the adjacent bone, Type of radiation deliver y total bone dose, and modes of radiation appeared to influence the ri sk of ORN occurrence, After conservative treatment, 44 (42.3%) cases h ad complete healing and resolution 34 (32.6%) cases had a stable, chro nic ORN process, and 26 (25.1%) cases had acute and progressive ORN. C onclusion: An understanding of the risk factors is important in preven ting ORN after radiation therapy.