抄録
The changes of the rat periodontium in experimental traumatic occlusion were studied histopathologically and autoradiographically. Forty seven rats received. excessive amalgam fillings in the right maxillary first and second molars. The animals were sacrificed at 1, 3, 5, 7, 10, 14, 35 and 65 days. The periodontium of the right mandibular fast molar was observed histologically. After receiving amalgam fillings, sixteen rats were intraperitoneally injected with 5 µc of 3H-proline per gram of body weight. They were killed at 3, 7, 10 and 14 days after injection. The periodontium of the right mandibular first molar was studied autoradiographically as the experimental side. The initial injury of the periodontium was already observed at 1 day and the injury became most severe at 7 days. But after 7 days the injured areas were gradually repaired and by 14 days they were almost restored to the normal condition. The histopathologic changes of the periodontium in the injury or repair process were characterized by decreased or increased cellularity and necrosis of the periodontal membrane, narrowing or widening of the periodontal space and resorption or regeneration of alveolar bon e and cementum. The osteoporotic changes of the alveolar bone were not observed. There were no definite adaptive alterations in the morphology of the periodontium after traumatic tissue changes disappeared. The most affected area was the bifurcation. No pocket formation or gingival inflammation was found in all of the experimental animals. Collagen formation in the periodontal tissues except the periodontal membrane at the distal root apex was already depressed in the initial experimental periods by traumatic occlusion. The formation of the alveolar bone was more influenced by occlusal disharmony than that of the cementum.
