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Pathological Study of Experimental Luxation Injuries in Immature Rat Teeth

未成熟大鼠牙齿实验性脱位损伤的病理学研究

基本信息

批准号：
01571114
负责人：
TAKAGI Yuzo
金额：
$ 1.34万
依托单位：
Tokyo Medical and Dental University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1991
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-01571114/
关键词：
Dental Trauma Luxation Injury Immature Teeth Rat 予後観察予備観察

项目摘要

School children have a relatively high incidence of luxation injuries to the immature permanent teeth. The luxated teeth often develop necrosis of the pulp, obliteration of the pulp cavity, and internal and external root resorption as a long-term reaction to the injury. The pathology and the degenerative processes of the complications, however, are not well understood. The influence of the fixation procedure to the prognosis of the luxated tooth also remains unclear.In this study, we histologically examined the long-term reactions of immature rat teeth after standardized luxation injuries delivered in our previously developed experimental model.Soon after the trauma, the periodontium at the pressure site had irregular fibers, degenerated cells and hemorrhage. The periodontium at the tension site suffered hemorrhage. The periodontal fibers on the tension side were elongated and, in some areas, torn. After 12 hours, a cell free area appeared in the periodontium on' the compression side. In the alveolar bone and on the surface of the root, resorption occurred one day and 5-7 days after injury respectively. Although the damage in the periodontium and alveolar bone was gradually repaired, the root resorption, especially in the cervical region on the compression side, continued throughout the experimental period. In the most cases, the dental pulp did not seem to be damaged immediately after the trauma. By the 7th day after injury, however, formation of irregular dentin was observed in some teeth. These changes of the pulp tended to disappear in the later stages of the experiment.The present data suggested that even with mild traumatic injury, the damage to the periodontal tissues locally will be severe. Also, the pulp cells were somehow disturbed in their function. Therefore, it is considered that the long-term follow-up is needed to the luxated immature permanent teeth.

学龄儿童未成熟恒牙脱位损伤的发生率相对较高。脱位的牙齿通常会发展成牙髓坏死、髓腔闭塞以及作为损伤的长期反应的内、外牙根吸收。然而，并发症的病理学和退行性过程尚不清楚。在这项研究中，我们从组织学上研究了未成熟大鼠牙齿在我们以前开发的实验模型中标准化脱位损伤后的长期反应。创伤后不久，压力部位的牙周组织有不规则的纤维，退化的细胞和出血。张力部位牙周组织出血。张力侧的牙周纤维被拉长，在某些区域被撕裂。12小时后，压迫侧牙周组织中出现无细胞区。牙槽骨和牙根表面分别于伤后1d和5-7 d发生吸收。虽然牙周组织和牙槽骨的损伤逐渐修复，但牙根吸收，特别是在受压侧的颈部区域，在整个实验期间持续存在。在大多数情况下，牙髓在创伤后似乎没有立即受损。伤后第7天，部分牙出现不规则牙本质形成。实验后期牙髓的这些变化趋于消失，提示即使是轻微的创伤，局部牙周组织的损伤也是严重的。此外，牙髓细胞的功能也受到了干扰。因此，认为对脱位的未成熟恒牙应进行长期随访。