実験的歯牙唇側傾斜移動に伴う歯周組織の変化についての病理組織学的研究
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概要
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In orthodontic treatment, when an anterior tooth is moved labially, exposure of its root sometimes occurs owing to vertical resorption of the labial alveolar bone crest of the anterior tooth. Traumatic occlusion and excessive labial movement have been cited as the causes ; however, conclusive clarification has not yet been made. Tipping an anterior tooth labially independent of the effects of traumatic occlusion and excessive labial movement was thought to clarify the cause leading to exposure of the root owing to vertical resorption of the labial alveolar bone crest of the anterior tooth. Therefore, for the purpose of determining the effect of artificial labial tipping movement of an anterior tooth on periodontium, especially on the labial alveolar bone crest, the upper second incisors in 18 mature dogs were tipped labially with a load of 200g. The experimental periods were for 1st, 2nd, 4th and 8th weeks, and add 8th weeks of movement and 2nd weeks of retention. At the end of each experimental period, a histological investigation was made. The results were as follows : 1. The labial alveolar bone crest in the experimental groups became the pressure side and showed the findings of resorption throughout the period but no remodeling. 2. The labial alveolar bone crest in the retention group showed neither remodeling nor resorption. No recovery of the bone was seen but the bone tended to stabilize. 3. The palatal alveolar bone crest became the tension side and showed the findings of remodeling throughout the experimental period for both the experimental and retention groups. No findings of resorption were seen. 4. The periodontal ligament showed irregularity in running and proliferation of young connective tissues throughout the period of tooth movement. The retention groups showed irregular running and proliferation of young connective tissues, although in lesser degrees as compared with the experimental groups. On the basis of the foregoing findings, vertical resorption of the labial alveolar bone crest when a tooth is moved labially is not limited to such causes as traumatic occlusion, as conventionally believed. It is perhaps more appropriate to consider the cause to be the matter of whether or not to exceeds the limits of adaptability of the living body.
- 九州歯科学会の論文
- 1990-04-25