【摘要】 目的:应用三维有限元法比较三种去粘接方法的优缺点。方法:建立牙-粘接剂-托槽系统的三维有限元模型,比较相同大小的剪切力、拉力和扭转力作用下,系统各部分的应力分布情况。结果:三种加载模式下,不同界面的应力和位移分布都是不均匀的;拉力加载条件下托槽/粘接剂界面的Von-Mises应力和最大主应力最大;剪切力加载条件下釉质/粘接剂界面的Von-Mises应力、最大主应力和位移变化最大。结论:单一加载条件下,拉力更容易产生界面的粘接破坏;剪切力加载条件下的应力和位移改变较大是其易引起釉面裂纹的原因之一。更多还原

【Abstract】 Objective:To compare the stress and displacement changing of three debonding methods used by in vitro bonding strength test.Methods:The three dimensional finite element model of the toothadhesive-bracket system was built and the shear,tensile and torsion with the same Newton were loaded at the corresponding location.The stress distribution and displacement changing of different loads in different interface were analyzed and measured.Results:Under the three different loads,neither the stress nor the displacement changing was uniform;The Von-Mises stress,the max principal stress and displacement of bracket/adhesive interface were larger than that of the enamel/adhesive interface.The Von-Mises stress and the max principal stress of the bracket/adhesive interface under tensile load was the largest among the three loads.Conclusion:In the single load cases,tensile load leads to interface failure easily;The largest changes of stress and displacement during shear load maybe one of the reasons that lead to enamel cracking.更多还原