Effects of 60CO-gamma-irradiation on the early ingrowth of an autogenous bone inlay into an artificial defect in the rabbit mandibula.

The incorporation of an autogenous humeral bone inlay into a previously irradiated mandibula was studied in 23 adult rabbits. A single exposure of 1000, 2000 and 3000 rads was given 1 or 8 weeks before the grafting into an artificially created defect in the rabbit mandibula. The observation time was 30 days. The results were compared to those obtained in 6 non-irradiated rabbits operated in the same way and after the same observation period. The callus formation around the graft was reduced to less than half the amount measured with morphometry in rabbits irradiated greater than or equal to 2000 rads one week preoperatively as compared to that in the non-irradiated group. The periosteal callus formed by the host bone was reduced with increasing preoperative radiation doses and the longer interval between irradiation and bone grafting. Practically all callus was formed by the graft constituents (particularly the periosteum) after heavier preoperative radiation doses and the longer interval between irradiation and bone grafting. The new bone formation started some days later and was of an inferior quality with larger preoperative doses and the longer interval between irradiation and bone grafting.