Histopathologic and roentgenologic studies on the effects of irradiation on the human mandibles

The present study deals with the pathologic change of the mandible following radiation therapy for oral cancer, histopathologically and roentgenologically. The results are summarized as follows: 1) As the resorptive change of the cortex and the trabeculae, irregular and bizarre resorption and enlargement of the lacunae were observed, 2) The grade of injury of the osteocytes was described by the percentage of the number of the lacunae, which were empty and in which the nuclei of the osteocytes could not be seen. Consequently these results correspond considerably well with the clinical aspects. 3) Osteophytes in the spongy and compact bone were observed, and also narrowing and plugging of the Haversian canal and the canal of Volkmann with mineral were seen as the sclerotic change. 4) Thickening of the tunica intima, obstruction, disarrangement of the elastic fibers and distruption of the vessels were observed in the inferior alveolar artery, the arterioles, and also occlusion, which gave various appearances, in the vessels within the Haversian canal and the canal of Volkmann was seen. 5) The following four groups, based upon the radiographic change, were classified as: Group I, irregular osteolytic change; Group II, marked osteosclerotic change; Group III, irregular mixture of osteolytic and osteosclerotic change; and Group IV, no remarkable change.