Electron Microscopic Studies on Osteoclastic Bone Resorption

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The present studies were intended to investigate the process of the osteoclastic bone resorption under several conditions and to clarify the structures and functions of osteoclasts and the mechanism of bone resorption. The results were summarized as follows:1. Comparative studies on osteoclastic bone resorption: The regions of bone resorption in rats were examined by histologic, scanning electron microscopic(SEM) and transmission electron microscopic(TEM) methods. The findings observed by SEM were consistent with the histological findings and those of TEM. It indicated that the comparative morphological investigation is one of the necessary and useful procedures.2. Effect of Indomethacin(IM) on osteoclastic bone resorptioin: In order to investigate the effect of IM on osteoclastic bone resorption in experimentally induced inflammatory lesion of periodontal tissue in rats, the resorption at the interdental bone induced by insertion of elastic band was examined histologically and ultrast … More ructurally. In the IM administrated rats, the reduction of the osteoclastic bone resorption was observed. It seems that the reduction of the bone resorbing activity is a consequence of the inhibition of prostaglandins (PGs) synthesis caused by IM. These results suggest that PGs play an important role on the osteoclastic bone resorption in inflammation of periodontal tissues.3. Osteoclastic bone resorption in the healing process of the extraction wound: In order to investigate the role of the bone resorption in the healing process of the extraction wound, the process in IM administrated rats was examined histologically and ultrastructurally. In the IM administrated rats, the retardation of healing process related to incomplete bone remodeling, which was caused by the inhibition of osteoclastic bone resorption and the reduction of new bone formation, was observed. These findings suggest that IM inhibits pgs synthesis and consequently reduces the activity of bone resorption and remodeling. Thus, it is considered that PGs as one of the chemical mediators perticipate also in the healing process of extraction wound and that osteoclasts, associated with osteoblasts, play an important role in this process. Less