犬の根完成歯再植に関する実験的研究 根尖部硬組織を切除し歯髄を露出させた影響

Abstract

A considerable number of histopathological studies concerning replanted human and animal teeth have been carried out. Mature replanted teeth have not shown pulpal repair, except on rare occasions, in contrast to immature teeth.The purpose of the present investigation was to study whether the exposed pulp tissue, performed at the time of the operation, affects the tissue reactions of the pulp and periodontal membrane of replanted mature teeth.The materials consisted of 288 single-rooted teeth (incisors and first premolars) from 36 adult dogs. 144 teeth were replanted after hard tissue removal of root apex and pulp tissue exposure (experimental group). 144 teeth were replanted without hard tissue removal and pulp tissue exposure (control group). The observation periods were 1, 7, 14, 30, 90 and 180 days. The teeth were radiographed before sacrifice, and then, they were longitudinally sectioned at 6 pm in a bucco-lingual direction. The sections were stained with hematoxylin and eosin and the elastica-Masson.No difference was noted in the inflammatory reactions of the gingiva tissue between experimental group and control group, but a little more teeth discoloration was found in control group than in experimental group. In radiographic findings, 14 days after replantation, periodontal space was enlarged, but at 180 days it was almost normal in both groups.In the histopathologic findings, experimental group initially had severe inflammatory reactions, but repair occured through ingrowth of connective tissue that had reached the median pulp after 180 days. Cells containing hard tissue were postoperatively formed on both root canal walls and pulp. In control group, pulp inflammatory reactions were mild, but repair did not occur much more than in experimental teeth. Pulp necrotic changes were shown in the control group. No difference was noted in periodontal membrane healing between both groups.