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An in-vitro study under cyclic loading on post-and-cores for endodontically treated teeth without coronal extension

没有冠状延伸的经过牙髓治疗的牙齿的桩核循环加载下的体外研究

基本信息

批准号：
15390599
负责人：
FUKUSHIMA Shunji
金额：
$ 3.33万
依托单位：
Tsurumi University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15390599/
关键词：
core buildups Co-Cr alloy inner cap technique ferrule effect fracture test fracture strength fracture mode cyclic loading 繰返し荷重

项目摘要

Root fracture caused by post and cores occurs often in daily practice resulting in extraction of the teeth. In this study a new method of post-and-core restoration was developed using a thin layer of Co-Cr coping between cores and crowns and its effectiveness was examined by the static and cyclic loading tests.In the first research year, fracture strength and pattern of the post-and-cores with and without the Co-Cr coping were examined under the static loading using bovine teeth. As a result, the post-and-core with the Co-Cr coping was useful in the endodontically treated teeth with 0 mm and 1 mm coronal extension.In the second research year, two types of margin design, shoulder and beveled shoulder types, were examined under the cyclic loading. Each specimen immersed in 37℃ of water was added by the load of 300N with 1 Hz of 300,000 cycles. After cyclic loading the static loading was added also until the specimens were broken. As a result, the Co-Cr coping was found to be effective to improve the fracture strength in the beveled shoulder type of margin design, though not effective in the shoulder type. Highly decayed endodontically treated teeth remain in difficulties to artificially restore their crowns and very often indicate short longevity of the crowns. This in vitro study suggests the effectiveness of a thin layer of Co-Cr coping in the severe condition of endodontically treated teeth.

桩核引起的牙根折断在日常工作中经常发生，需要拔除牙齿。本研究提出了一种新的桩核修复方法，在核与冠之间覆盖一层薄的钴铬附着体，并通过静载和循环加载试验来检验其效果。在第一个研究年中，使用牛牙在静态载荷下检测有无钴铬附着体的桩核修复体的断裂强度和断裂型式。结果表明，钴铬桩核可用于冠伸0 mm和1 mm的根管治疗牙。在第二年的研究中，我们研究了两种边缘设计，肩型和斜肩型。每个试件浸泡在37℃的水中，加300N的载荷，1 Hz，300,000次循环。在循环加载后，还添加静力加载，直到试件破裂。结果发现，钴铬冠在斜肩型边缘设计中有效地提高了骨折强度，但在肩型中效果不佳。经过根管治疗的高度腐烂的牙齿在人工修复牙冠方面仍然存在困难，而且通常表明牙冠寿命较短。这项体外研究表明，在牙髓治疗的严重情况下，一层薄薄的钴铬覆盖层是有效的。