论文部分内容阅读
目的采用有限元方法对比分析不同厚度垫底材料对充填后牙体应力分布的影响。方法选用正常形态下颌第1磨牙,基于MicroCT扫描建立Ⅰ类洞充填的三维有限元模型,选择Vitrebond和Dycal作为垫底材料,分别考虑4种不同的厚度(0.5、1.0、1.5和2.0mm),施加250N的咬合力,对各模型中牙体、充填体和垫底材料的最大/最小主应力进行比较。结果 Dycal垫底,厚度为2.0mm,牙体的最大主应力峰值超过其抗拉强度,垫底材料的最大/最小主应力峰值分别超过其抗拉和抗压强度;垫底厚度为1.5mm和2.0mm,充填体的最大主应力峰值接近其抗拉强度的90%。Vitrebond垫底时,各材料的最大主应力峰值也都在1.5mm或2.0mm时达到极值。结论从防止充填后牙体折裂的角度,建议临床上采用较薄的垫底层厚度,取0.5～1.0mm。
Objective To compare the effects of different thickness of bottom material on stress distribution of post-filling tooth with finite element method. Methods Three-dimensional finite element models of type I cave filling were established by using MicroCT scanning. The vitrebond and Dycal were selected as the backing materials, and four different thicknesses (0.5, 1.0, 1.5 and 2.0 mm) 250N bite force to compare the maximum / minimum principal stresses of the dental, filling, and backing materials in each model. Results Dycal bottom, the thickness of 2.0mm, the maximum peak stress of the tooth exceeds its tensile strength, the maximum / minimum peak stress of the bottom material exceed the tensile and compressive strength respectively; the thickness of the bottom is 1.5mm and 2.0mm, The maximum principal stress peak of the filler body is close to 90% of its tensile strength. Vitrebond bottom, the maximum principal stress peak of each material also reached the extreme 1.5mm or 2.0mm. Conclusion From the perspective of prevention of tooth fracture after filling, it is recommended to use a thinner bottom layer of the thickness of the clinic, taking 0.5 ~ 1.0mm.