放射線照射の乳歯歯髄および歯根膜に及ぼす影響に関する実験的研究
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概要
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Left mandibular third deciduous molars of young dogs were irradiated for 3, 000R with 200kVp X-ray and the effect on the dental pulp and periodontal membrane was investigated histopathologically. The results were as follows : 1. From 3rd to 7th days after irradiation, localized inflammatory cell infiltration was observed in part in the dental pulp tissue. In the fiber bundles and blood vessel walls, deposition of hyalin stained lightly with eosin was beginning to be observed. No abnormal findings were observed in the periodontal membrane. 2. On 14th day after irradiation in the coronal dental pulp, cells decreased ; karyopycnosis occurred ; cells were connected only by cellular processes, and large and small reticular networks were formed. In the periodontal membrane, fibers ran irregularly although in part and findings of atrophy were seen. Fibroblasts showed a decreasing tendency. 3. In the cases from 1 to 2 months after irradiation, the pulp tissue showed marked atrophy of odontoblasts and the dental pulp showed hyalinization-like changes. Calcareous degeneration stained densely with hematoxylin was found scattered around the blood vessels. Although the pulp cells dicreased extensively but normal pulp cells were still found. In the periodontal membrane, Sharpey's fibers ran irregularly or became indistinct, and fibroblasts decreased extensively. The periodontal membrane in general showed hyalinization. 4. In the cases of 4 months after irradiation, the pulp tissue on the whole showed marked atrophy and disappearance of odontoblast layers. From the coronal dental pulp to the root pulp, reticular atrophy and hyalinization were seen. In the periodontal membrane, inflammatory cell infiltration was seen in part and membrane fibers, as those in 2nd month, showed marked atrophy, became enlarged, and presented findings of hyalinization. 5. At 8th month, the nucleoli nearly disappeared in the pulp tissue from the crown to the root and the cells were connected like filaments by cellular processes. Nearly all the blood vessels and fibers disappeared. At this stage, Korff's fibers from the pulp to predentin were no longer observed. In the periodontal membrane, most of Sharpey's fibers disappeared. Fibroblasts showed marked atrophy and disappearance, and few normal fibloblasts could be found. In the cementum and alveolar bone, marked resorption was seen. In the resorbed region of the cementum, apposition of cementum-like hard tissue was observed and the hard tissue adhered to the alveolar bone, and findings of bony ankylosis were observed.
- 九州歯科学会の論文