Dentin Barrier の形成機序に関する電子顕微鏡的検索 : とくに根未完成永久歯について

概要

論文の詳細を見る
Vital pulpotomy was performed on the immature permanent teeth of young adult dogs and formation process of the dentin barrier was investigated electron-microscopically. The results were as follows : 1. Three days after operation, the transmission electron microscope (TEM) observation of the region directly under the plane of the amputated pulp showed many undifferentiated mesenchymal cells poor in cell organellae around the blood vessels and a few collagen fibrils around these cells. 2. A week after operation, the TEM observation of the region below the site where formation of calcified barrier began directly under the amputated plane showed polygonal cells poor in chromatin and with wide intercellular space and depressed large nuclei, and a few collagen fibrils around these cells. 3. Two weeks after operation, the dentin barrier was beginning to be formed directly under the amputated plane. The scanning electron microscope (SEM) observetion of this region showed places where granular crystals and fibrous tissues aggregated in continuous alternate layers or fused together from the peripheries to the center of the pulp and some relatively void places remaining. The TEM observation of the center of the dentin barrier showed odontoblast-like cells with deeply depressed nuclei poor in chromatin, located eccentrically to the pulpal side, containing many mitochondria and rich in cell organellae such as rough-surfaced endoplasmic reticula, and joined with the adjacent cells by the junctional complex. The cells directly under the dentin barrier in the periphery had large oval nuclei poor in chromatin and located eccentrically to the pulpal side, and with mitochondria and cell organellae such as rough-surfaced endoplamic reticula unevenly distributed toward the dentin barrier. These cells presented findings similar to those of the odontoblasts in the root. 4. A month after operation, the SEM observation from the coronal side of the dentin barrier formed in the amputated plane showed fibrous deposits scattered in irregularshaped calcospherites and many ovoid defects of various sizes in this region. The observation from the pulpal side showed orderly openings of dentinal tubules and many indistinct borders with irregular matrix. The TEM observation of the odontoblasts directly under the dentin barrier showed in all regions odontoblasts presenting identical findings to those odontoblasts in the root which had large oval nuclei poor in chromatin and located eccentrially to the pulpal side. contained mitochondria and rough-surfaced endoplasmic reticula, and were joined by the junctional complex. 5. Two months after operation, the SEM observation of the dentin barrier formed in the amputated plane showed tissue fusion with primary dentin and smooth surfaces continuously from the peripheries to the center of the pulp. The TEM observation of this region showed highly active odontoblasts. 6. Four months after operation, the SEM obsesvation of the dentin barrier showed smooth surfaces formed continuously from the peripheries to the center of the pulp in the longitudinal section, and orderly distribution of many calcospherites and clear structures of dentinal tubules, distinct borders with matrix, and findings about similar to those of the odontoblasts in the root, in the pulpal section. The TEM observation of the cells directly under the dentin barrier showed odontoblasts with oval nuclei and with developed rough-surfaced endoplasmic reticula and mitochondria located eccentrically to the dentin barrier, and also showed odontoblasts with expanded cristae of mitochondria.
九州歯科学会の論文
1989-08-25

Dentin Barrier の形成機序に関する電子顕微鏡的検索 : とくに根未完成永久歯について

スポンサーリンク

概要

著者

関連論文

スポンサーリンク