摘要
目的:模拟磨牙根管治疗后全瓷嵌体冠修复的有限元模型,分析髓室底垫底厚度对应力分布的影响.方法:利用Micro-CT扫描数据建立离体下颌第一磨牙三维有限元模型,模拟复合邻面洞型并用嵌体冠进行修复.根据玻璃离子垫底厚度不同分为0(空白组)、1、2、5 mm(窝洞填平)组,然后分别采用轴向和45°斜向静态加载模式对模型加载280 N和105 N的力,观察不同部位的应力分布情况,分析比较应力集中部位及相应部位应力峰值的差异.结果:不同垫底厚度在相同的加载条件下,应力的集中部位相似.与0 mm组相比,当垫底厚度为1 mm,轴向加载时,髓室底的等效应力减小13.8％(45°加载时减小26.8％),粘结层剪切应力减小1.1％(45°加载时增加1.4％),远中肩台应力减少3.0％(45°加载时增加1.3％);垫底厚度为2 mm,轴向加载时,髓室底的等效应力减小31.1％(45°加载时减小41％),粘结层的剪切应力增加3.7％(45°加载时增加33.2％),远中肩台的等效应力减小0.6％ (45°加载时增加1.6％);垫底厚度为5mm,轴向加载时,髓室底的等效应力减小37％(45°加载时减小49.1％),粘结层的剪切应力增加13％(45°加载时增加47.2％),远中肩台的等效应力增加7.3％(45°加载时增加10.5％).结论:对根管治疗后的磨牙嵌体冠修复时,较薄的垫底厚度有利于剩余牙体和嵌体冠的稳定.
Abstract
AIM:To evaluate the effects of cement thickness on the full-ceramic-endocrown restoration using a finite element analysis model.METHODS:A finite element analysis model of mandible first molar was established using the scanning data acquired by Micro-CT.The misio-occlusio-distal cavity and endocrown restorations were simulated.The models were lined with Fuji Ⅸ glass ionomer cement.Based on cement thickness of 0,1,2 and 5 mm.A static axial and 45° loading 280 N and 105 N were respectively applied to each model.RESULTS:Compared with 0 mm group,when the glass ionomer was under 1 mm/axial condition,equivalent stress of pulp chamber floor decreased by 13.8％ (under 1 mm/45° decreased by 26.8％),shear stress of bonding layer decreased by 1.1％ (under 1 mm/45° increased by 1.4％) and equivalent stress of the distal surface of the remaining tooth decreased by 3.0％ (under 1 mm/45° increased 1.3％).Under 2 mm/axial condition equivalent stress of pulp chamber floor decreased by 31.1％ (under 2 mm/45 ° decreased by 41％),shear stress of the bonding layer increased by 3.7 ％ (under 2 mm 45° increased by 33.2％) and equivalent stress of the distal surface of the remaining tooth decreased by 0.6％ (under 2 mm/45° increased by 1.6％).For the 5 mm/axial group,equivalent stress of pulp chamber floor decreased by 37％ (under 5 mm/45° decreased by 49.1％),shear stress sof the bonding layer increased by 13％ (under 5 mm/ 45° increased by 47.2％) and equivalent stress of the distal surface of the remaining tooth decreased by 7.3％ (under 5 mm/45° increased by 10.5％).CONCLUSION:When endocrown is used for the restoration of endodontically-treated molar,a thinner cement thickness has a better effect for the long term stabilization of abutment and the endocrown.
NETL
NSTL
维普
万方数据