乳歯歯髄切断後の Dentin barrier に関する実験的研究
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概要
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Dentin barriers formed after pulpotomy of deciduous teeth in young dogs were investigated radiologically, photographically, microscopically, scanning electron microscopically, and with X-ray analyser. The results were as follows : I. Radiological and photographic observations 1. On the 14th day after operation, radio-opaque image appearing directly below the plane of section was observed as a linear pattern and the image in the microphotogram was observed as a low densitometrical curve as compared with primary dentin. The value equivalent to aluminium was 1.47mm. 2. On the 21st day, the radio-opaque image directly below the plane of section showed a wide belt-like pattern and the image in the microphotogram was observed as a low densitometrical curve as on the 14th day. The value equivalent to aluminium was 1.55 mm and showed an increase. 3. On the 35th day, the radio-opaque image increased its width and thickness and appeared sharply. In the microphotogram, the image appeared as a densitometrical curve with less identations and showed an increase as compared with that on the 21st day. The value equivalent to alminium was 1.70mm and showed a further increase in thickness. II. Microscopic and Scanning Electron Microscopic Investigations 1. On the 14th day after operation, formation of calcified bridges was observed microscopically in the plane of section and organic matrixes were also seen in part in the innermost layer of the bridges. Electron microscopically, granular materials of various sizes were seen in irregular arrangements on the coronal side and spiral fibrous structures were abundant around them. On the pulpal side, fusion of round and ovoid crystal structures of various sizes was observed. In the longitudinal section, although aggregation of granular calcified materials was seen, communication of the dental pulp and the coronal side was observed. 2. On the 21st day, microscopically, mixed findings of calcified bridges and early stage of formation of dentin barriers were observed. Electron microscopically, the coronal side had smooth and rough surfaces and consisted of crystalites of various sizes and thin fibrous structures. On the pulpal side, small crystalites, 0.1-1.0μm in diameter, were fused together, but many slits were still observed. In the longitudinal section, spaces were seen in the surface portion but crystal structures were fused around the spaces. On the pulpal side, openings of dentinal tubules were observed. 3. On the 35th day, formation of dentin barriers and also penetration of Korff's fibers into the barrier were observed. Electron microscopically, granular materials were dense on the coronal side and apertures, 0.1-5μm in diameter, were observed in places. Although tubular openings were seen, distinction between peritublar dentin and intertubular dentin was unclear. On the pulpal side, most portions excluding the central portion consisted of calcosherites and organization was formed. Apertures were observed in it and they were especially many at the peripheries. In the central portion, the barrier was observed as predentin-like structure. In the longitudinal section, the barrier was as dense as the root and formed flat surfaces. III. Analysis by X-ray analyser X-ray analysis of the dentin barrier formed on the 35th day showed two patterns : Ca and P were about the same in peak. The peak of Ca which is similar to primary dentin was a slightly higher than that of P.
- 九州歯科学会の論文
- 1986-10-25