残髄に関する実験的研究

Abstract

The author experimented with the use of permanent teeth of dogs on purpose to retain a residual pulp in the more apical portion (Low Positional Pulpotomy) and in the more coronal portion of root pulp (High Positional Pulpotomy) with the use of medicament Calvital (a commercial form of calcium hydroxide) and the other six sorts of root canal filling medicament, a histopathological study to the healing process of residual pulp was made and summerized as follows ; 1. The case, which is the case of closing the wound surface of the pulp by the newly formed dental hard tissue, "so-called dentine barrier" was observed more in the group of High Positional Pulpotomy than in the group of Low Positional Pulpotomy. 2. Histologic structure of the dentine barrier was observed in various appearances from primary dentine to osteoid dentine, but the formation of these barrier was considerd as closely related not only to the function of pulp tissue, but also to the effects by the sort of medicaments used. 3. The formation of these barrier was observed most in cases of the used medicaments, Calvital and Calsan A and showed a tendency that the beginning of the formation was about 10 days postoperatively and the complete closure of the wound pulpal surface was about 20 days postoperatively. The structural condition and the thickness of the barrier were fairly better in case of the used medicament, Calvital. 4. When the High Positional Pulpotomy procedure was employed, each medicament made some differences to the reactive change in the pulp, but in relation to the successive change, some roughly regular changes were observed. When the Low Positional Pulpotomy procedure was employed, however, there were many cases which showed that a great deal of reactive change, caused by the instrumental effect due to the difficulties of the procedure, and there were a few cases which showed regular successive and histological changes to the medicaments used. 5. In case of Low Positional Pulpotomy employed, there were many cases, showed that the root canal were overfilled due to the difficulties of filling technic, moreover, induration or degeneration of the residual pulp tissue due to the instrumental oppression was observed. 6. On a reactive change in the pulp to the pulpotomy procedure employed or each medicament used, the most cases of High Positional Pulpotomy group showed that the reactive changed area was localized within the pulp, but the most cases of Low Positional Pulpotomy group showed that not only induration or degeneration already mentioned above, in an early stage, but also inflammation in the residual pulp occured within 20 days postoperatively and then, the inflammation infiltrated into the periapical tissues. 7. It was proved that the cases of Calbital and Calsan A out of the medicaments used in the present study were most favorable to healing of the wound residual pulp throughout the experimental groups of High Positional Pulpotomy and Low Positional Pulpotomy procedure and followed by N_2 and YOSHIDA Paste, but Triozinc Paste, Canals and Propac were unfavorable. 8. Although it is too hasty to apply the human cases from these results obtained in this present study, moreover, as an attempt to retain a residual pulp in the apical portion may give rise to seriously uncomfortable findings, which are the appearances of lesion of tissue and the subsequent extension toward the periodontal tissues due to the difficulty and instability of the subsequent filling procedure, it seems to be necessary that the pulp should be retained as much as possible on its volume in case of pulpotomy procedure and be removed completely to the root end in case of pulpectomy procedure.