乳歯歯髄切断後の創傷治癒に関する神経組織学的研究
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概要
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As a part of a study of healing process of wounds after pulpotomy on deciduous teeth, changes in nerve fibers of the central portion after cutting the peripheral nerves were investigated neurohistologically with use of deciduous teeth of young dogs characterized by physiological root resorption. The results were as follows : 1. Formation of a necrotic layer directly under the plane of section of the pulp and coagulation of red cells in the blood vessels were observed. Although almost all the nerve fibers disappeared, some nerve fibers about to lyse and disappear while swelling were also observed along the blood vessels running toward the plane of section. 2. On the third day after operation, a layer showing von Kossa positive reaction or what is called the line of demarcation was observed in the border between the necrotic layer and the living pulp, and a slight reactive inflammatory state was observed in the pulp. Some nerve fibers while swelling penetrated from the pulp and through the demarcation line into the necrotic layer and disappeared. In the still existing nerve bundles, some degenerative nerve fibers which ran straight toward the demarcation line, retained stainability and changed their running directions along the demarcation line were also observed. In the slightly lower pulp, nerve fibers which were swollen, lacerated, or granulated were observed. In the central portion between the middle root canal and the root apex, no degenerative nerve fibers were seen. 3. On the 7th day after operation, consentration of collagenous fibers and formation of a calcified barrier containing cells with a large neucleus each were observed in the plane of section. The reactive inflammatory state in the pulp was very slight as compared with that on the third day. As to nerve fibers, some nerve bundles previously existing still remained in the barrier but were degenerated. In the pulp directly under the barrier, regenerated nerve fibers accompanied by Schwann's cells were extending actively but some terminated just short of reaching the barrier. 4. In the cases on the 21st day, formation of a dentin barrier was observed in the cut portion and structures of dentinal tubules were seen. In the innermost layer of the barrier, formation of wide young dentin containing cells was seen, and along with this, arrangement of odontoblast-like cells was seen. Small nerve bundles, minute nerve fibers, and single nerve fibers appeared but nerve fibers penetrating into the odontoblast layers were rarely seen. 5. On the 35th day, along with the formation of dentinal barriers, argyrophile fibers or what is called Korff's fibers from the pulp meandered between odontoblasts and penetrated into young dentin. Minute nerve fibers branching out from small nerve bundles abounded, intersected, anastomosed and formed nerve plexuses. Some of the never ending were seen penetrating into the odontoblast layers.
- 九州歯科学会の論文
- 1984-12-25