放射線治療による顎骨障害に関する研究

抄録

Following the radiation therapy for oral cancer, radiation osteitis or osteoradionecrosis often occurs in jaw bones than the other skeletal bones, because of the fact that jaw bones are easily affected with bacterial infection. Clinical and radiographical analysis of the radiation osteitis in jaw bones, and to clarify the relationship between the mandibular absorbed dose and radiation osteitis as well as the etiologicfactors, are not only important for carrying out radiotherapy but also of great significance in relation to the prophylaxis or the inhibition of radiation osteitis, and further they will serve to give many suggestions for dental treatments to be done later.
In this study, the radiation injury of jaw bone following radiotherapy was analysed clinically and radiographically in detail and the criteria in radiographic diagnosis at early stage of the development of radiation osteitis were established. The relationship between the mandibular absorbed dose and radiation osteitis as well as the etiologic factors was also investigated, and further the correlation between the occurrence of radiation osteitis and the tooth extraction as well as the time of its performance at the irradiated site was experimentally pursued.
As the results, radiation osteitis appeared relatively at earlier time after radiotherapy, and it was found out that a radiographic diagnosis at an early stage was possible to be made by means of periodical x-ray examinations as being judged from its typical radiographicchanges. Also at the time of external irradiation for oral cancer, the irradiated side of jaw bone was included within the range of 100 % of depth dose but in the case of interstitial irradiation the absorbed dose of bone was less influential. It was made clear that the incidence of radiation osteitis caused by tooth extraction etc. was more frequent when the TDF value at jaw bone was less than 90, and it was liable to cause radiation osteitis even if no etiologic factor was present when the TDF value was more than 100. Further, it was suggested that radiation osteitis was apparently induced by tooth extraction from the experimentalresults in rats, and that the occurrence of radiation osteitis can be inhibited when the radiotherapy was not allowed to start until the time when the formation of granulation tissue at the socket is considered active.