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FEM Investigation on Formation Mechanism and Resolution of Wedge-shaped Defect Induced by Occlusal Form

咬合形态引起的楔形缺损形成机制及解决的有限元研究

基本信息

批准号：
18592095
负责人：
CHEN Ker-Kong
金额：
$ 1.2万
依托单位：
Kyushu Dental College
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2006
资助国家：
日本
起止时间：
2006 至 2007
项目状态：
已结题

项目摘要

Abfraction is known to have great deal with the formation of wedge-shaped defect (WSD). The finite element method (FEM) studies have confirmed that the stress concentration area during loading is consistent with the frequently observed WSD region. However, those FEM results were obtained by using 2-D FE model instead of 3-D FE model because of the difficulties in constructing the complex anatomical morphology and occlusal surface. This study used 3-D FE model to investigate the stress distribution by focusing on the cervical region under various occlusal loading and to find out the resolution for WSD by FEM. The 3-D FE model was constructed by using micro CT images of maxillary premolar and its validity was also examined. Furthermore, the distribution of principal stress occurred at cervical region enamel from mesial, buccal to distal surfaces (cemento-enamel junction) was measured under loading (loading points: tip of lingual cusp, mesial marginal ridge and distal marginal ridge) in a direction parallel to tooth axis or in an inclination of 15, 30, 45 degrees to tooth axis. The results were as follows.1) 3-D FE model was successfully reconstructed to reveal the tooth anatomical morphology by the use of micro CT images.2) The analytical value of stress obtained from 3-D FE model was consistent with the value detected by strain gauge that attached on tooth cervical region. It is indicated that the 3-D FE model is suitable to replace tooth for further FEM investigation.3) The principal tensile stress occurred around the cemento-enamel junction became larger with the increasing inclination of loading force. However, the tensile stress can be relieved by adjusting the number of loading points or loading ratio in those loading points. It is suggested that the appropriate contact patterns can not only relieve but also inhibit the formation of WSD.

摘要对楔形缺陷的形成有很大的影响。有限元法研究证实，加载过程中的应力集中区域与经常观测到的WSD区域一致。然而，由于难以构建复杂的解剖形态和咬合面，这些有限元结果是采用二维有限元模型而不是三维有限元模型得到的。本研究采用三维有限元模型研究不同咬合载荷下颈椎区域的应力分布，并利用有限元方法对WSD进行解析。利用上颌前磨牙显微CT图像建立三维有限元模型，并对模型的有效性进行验证。此外，在加载（加载点：舌尖尖尖、中缘脊和远缘脊）方向平行于牙轴或与牙轴倾斜15度、30度、45度)的情况下，测量颈区牙釉质从近中、颊面到远端面（牙釉质交界处）的主应力分布。结果如下：1)利用显微CT图像成功重建三维有限元模型，揭示牙齿的解剖形态。2)三维有限元模型得到的应力解析值与附着在牙颈区域的应变片测得的应力值一致。结果表明，三维有限元模型适合于进一步的有限元研究。3)随着加载力倾斜度的增大，牙骨质-牙釉质结合处的主拉应力增大。可通过调整加载点的数目或加载点的加载比来减小拉应力。结果表明，适当的接触方式既能缓解也能抑制水垢的形成。