根未完成永久歯再植後の根尖周囲組織の治癒過程に関する X 線学的, 光顕的ならびに透過型電子顕微鏡的研究

概要

論文の詳細を見る
The immature permanent teeth of young adult dogs were luxated completely and then replanted, and the healing process of the periapical tissue and apical closure were examined radiologically, light microscopically, and transmission electron microscopically. The results were as follows : 1. Radiological findings In the control group, lamina dura and periodontal space became distinct in the second months after operation, and apical closure was about completed in the fourth months. The experimental group showed shorter root length than the control group. The apical portion was indistinct owing to the examination of closure through the periodontal membrane and accelerated radio-opacity from the dental pulp toward the apical portion at two months and thereafter. 2. Light microscopic and transmission electron microscopic findings A. In the control group three days after operation, Hertwig's epithelial sheath was observed at the apical portion. An observation of this portion under the TEM showed that highly active cementoblasts passed through the Hertwig's epithelial sheath and appeared in the surface of the apical dentin. In the experimental group, the cells of the Hertwig's epithelial sheath were degenerated. The cells at this site were dark and cell organellae were swollen and disintegrated under the TEM. Cell debris and ruptured collagen fibrils were also seen. Some normal cell organellae were observed in part. B. Of the cases one month after operation, the control group was in an early stage of addition of cementum with cells at the apical portion and the root apex was still open. In the experimental group, large qauasi-round cells containing cement-like hard tissue were formed at the apical portion. Under the TEM, highly active cementoblasts with aboundant rough endoplasmic reticulum and with clear nucleoli were observed in the surface of the cement-like hard tissue. C. The findings at two months and thereafter after operation showed Type III healing. In Type I healing, tissue union occurs between the hard tissue, which is adjacent to young dentin at the apical portion and with irregular dentinal tubules in part, and osteodentine formed in the dental pulp, and the cement-like hard tissue added to the apical portion. Apical closure is observed through the periodontal membrane. In Type II healing, osteodentine is added to the young dentin at the apical portion and the dental pulp is occupied by osteodentine. The alveolar bone at the apical portion clearly proliferate but apical closure is not observed. In type III healing, the alveolar bone invades into the dental pulp tissue and tissue union with osteodentine in the dental pulp occurs ; no apical closure is observed. D. The periodontal membrane showed in part ruptured fiber bundles and disorderly running in the cases from one to six months after operation but presented about normal image on the root side. An observation after silver staining showed about the same findings. E. In the cases four months and thereafter after operation, a TEM observation showed that the cementoblasts at the cement-like hard tissue region had nuclei rich in chromatin and a small number of cell organellae and presented the state of so called resting cells. In some parts of the surface of cementum, bundles of collagen fibers penetrated and interfascicular cementoblasts were seen, and in others, entrance of collagen fiber bundles was hardly seen and cementoblasts were arranged.
九州歯科学会の論文
1988-02-25

根未完成永久歯再植後の根尖周囲組織の治癒過程に関する X 線学的, 光顕的ならびに透過型電子顕微鏡的研究

スポンサーリンク

概要

著者

関連論文

スポンサーリンク