Osteoradionecrosis of mandible in patients treated with definitive radiotherapy for carcinomas of oral cavity and oropharynx. A retrospective study.

: A retrospective analysis of 1140 cases of cancer of oral cavity and oropharynx treated with definitive radiotherapy was carried out with regard to the incidence and precipitating factors of mandibular osteoradionecrosis. 14 cases developed osteoradionecrosis out of which 10 had spontaneous mandibular necrosis and 4 had dental extractions in the area where osteoradionecrosis developed. Amongst the 10 cases of spontaneous osteoradionecrosis, 8 patients received doses of 6500 cGy in 6 1/2 weeks or 7000 cGy in 7 weeks by megavoltage cobalt 60 teletherapy and the remaining two patients received the doses of 6000 cGy in 6 weeks. The aforesaid 4 patients of osteoradionecrosis in the area of dental extractions had received doses of only 6000 cGy in 6 weeks.