[Micrographic aspect of mandibular osteoradionecrosis (author's transl)].

Fragments of the lower jaw from 42 patients with carcinoma of the oral cavity or oropharynx, and treated primarely with fraction radiotherapy, were excised for radiation osteonecrosis 6 month to 10 years after irradiations. The excised specimens are X-rayed before being coated with methylmetacrylate. They are then cut into thick sections along lines detailled on the X-ray films. The sections are trimmed to 80 microns and examined microradiographically. Two observations are sufficient to demonstrate destruction or reorganisation of the bone tissue. Reabsorption of unusual appearance is seen around the Haversian canals. The newly formed tissue resembles either embryonic bone matter, or lamellar tissue as seen in osteomyelitis.