边缘肩台宽度对上颌中切牙邻面洞树脂修复后应力的影响

The effect of the shoulder width on the stress of resin filled proximal caries of maxillary central incisor

目的:探讨不同窝洞边缘肩台宽度对树脂充填上颌中切牙邻面洞后应力的影响。方法:以形态、大小正常的人上颌中切牙为对象,通过逆向工程技术建立上颌中切牙邻面洞的三维有限元模型,并对其进行边缘扩展,同时将其肩台宽度分别设计为0、0.5、1、1.5 mm;然后再运用三维有限元法分析不同肩台宽度对充填后的树脂、粘结界面以及牙体组织最大主应力的影响。结果:各实验组的最大主应力分布相似,即树脂的最大主应力主要集中于加载点附近,粘结界面的最大主应力集中于粘结边缘,牙体组织的最大主应力集中于牙颈部;随着肩台宽度的增加,树脂和粘结界面的最大主应力均逐步减小,而牙体组织的最大主应力几乎无变化。结论:宽度为1.5 mm的肩台边缘扩展可以有效增加树脂粘结面积,并降低树脂和粘结界面的最大主应力。

AIM： To investigate the effects of different shoulder width on the stress of resin filled proximal caries of maxillary central incisor.METHODS： A 3D finite element model of proximal caries of maxillary central incisor with different shoulder width was established by reverse modeling method.According to the design of shoulder, the models were divided into 4 groups： 0, 0.5, 1 and 1.5 mm.The influence of different width of shoulder on maximum stress of resin, adhesive interface and tooth were analyzed by 3D finite element method.RESUTLS： The maximum principal stress distribution is similar in the 4 experimental groups.The stress of resin was mainly concentrated in the load point;the stress of adhesive was concentrated in the bonding interface edge;the stress of tooth was concentrated in the tooth neck.With the increase of the shoulder width, the maximum principal stress of the resin and the bonding interface was decreased, however, the maximum principal stress of the tooth had no change.CONCLUSION： The edge extension of the shoulder with a width of 1.5 mm can effectively increase the resin adhesive area and reduce the maximum principal stress of the resin and bonding interface.