垫底厚度对全瓷嵌体修复应力分布影响的三维有限元分析

Three dimension finite element analysis of different base thickness on stress distribution of ceramic inlay

目的通过对不同垫底厚度上颌前磨牙全瓷嵌体修复进行三维有限元分析,了解垫底厚度对全瓷嵌体修复应力分布的影响。方法建立垫底厚度分别为0.5mm,1.0mm和1.5mm的上颌前磨牙邻面缺损嵌体修复三维有限元模型,采用3种垫底材料,应用ANSYS10.0有限元分析软件,计算分析应用3种不同厚度垫底时,嵌体和剩余牙体组织的应力分布状况。结果随着垫底厚度的变化,嵌体、牙釉质和牙本质的最大拉应力,以及粘结剂层的最大剪切力均发生变化。嵌体的最大拉应力、粘结剂层的最大剪切力随着垫底厚度的增加而逐渐增加,当垫底厚度为0.5mm时牙釉质中的最大拉应力最小,而牙本质中的最大拉应力最大。使用不同垫底材料时,随垫底厚度增加,嵌体中的最大拉应力上升的幅度有所不同,玻璃离子垫底组上升的幅度最大,复合体组次之,树脂垫底组上升幅度不明显。结论弹性模量较低的垫底材料其厚度的变化对嵌体应力改变的影响明显,弹性模量高的垫底材料其厚度的变化对嵌体应力改变的影响不明显。

Objective To analyze the stress distribution of ceramic inlay with different base thickness. Methods A three-dimension finite element model of maxillary premolar with class II cavity restored by ceramic inlay with different base thickness was established. The thicknesse of base materials was 0mm, 0. 5mm, 1.0mm and 1.5mm, respectively. The maximum tensile stress in the tooth, ceramic inlay, base material and adhesive layer was recorded. Results The maximum tensile stress in the ceramic inlay, base and adhesive layer increased when the base thickness increased. The maximum tensile stress in enamel was the lowest when the base thickness was 0. 5mm, while in dentine it was the highest. The maximum tensile stress in the inlay varied with the increase of the base thickness. Conclusion The maximum tensile stress in the ceramic inlay was significantly influenced by the thickness of base material with lower elastic modulus.