托槽底板金属丝网格密度影响托槽黏结强度的三维有限元分析

背景：牙齿正畸领域中托槽黏结质量受很多因素影响,不同的托槽底面设计会影响托槽的黏结强度,但目前的实验方法均不能准确量化牙齿的黏结强度。目的：通过建立托槽-黏结剂-牙齿的三维有限元模型,分析托槽底板金属丝网格密度对黏结强度的影响。方法：利用商业有限元软件ANSYS,参考CT扫描图像并结合标准方丝弓托槽的数值,建立牙-黏结剂-托槽系统的三维有限元模型。计算分别在相同大小的剪切力和扭转力加载作用下,0.2mm和0.4mm网丝间距的托槽底板的应力分布。结果与结论：0.4mm间距的网丝局部危险应力显著小于0.2mm间距的网丝局部危险应力,0.4mm间距的网底抗破坏能力优于0.2mm间距的网底。说明在保证黏结剂固位型的情况下,网丝间距越大,即网孔面积越大,黏结剂自身抗破坏能力越强,托槽黏结强度越大。

Three-dimensional finite element analysis of bond strength by bracket base metallic wire mesh space

BACKGROUND： Bond strength of the bracket is influenced by many factors in orthodontics, different bracket-base designs exert influences on bond strength, and the present experimental methods are not able to exactly describe the bond strength in view of quantitative research. OBJECTIVE： To construct a three-dimensional finite element model of the bracket-cement-tooth and to analyze the influence of bracket base metallic wire mesh space on bond strength. METHODS： A validated three-dimensional finite element model of the bracket-cement-tooth system was constructed with the ANSYS commercial software based on CT scanning image and standard wire arch bracket values. The stress distribution in different mesh space （0.2 mm and 0.4 mm） of the brackets was calculated under the same the shear force and twist force. RESULTS AND CONCLUSION： 0.2-mm mesh space had a significantly greater peak stress than 0.4-mm space, but the resistance to the destruction was lower than 0.4-mm space. The bigger the mesh space is, the larger the mesh area is, the stronger the resistance to destruction is, the better the bond strength becomes on condition that the retention form of the cement remains intact.