复合树脂修复Ⅰ类洞型后的三维有限元分析

目的比较复合树脂修复I类洞型后在不同力情况下,定量研究牙合力因素对牙体组织及修复体应力大小和分布的影响,分析其可能对牙体组织和修复体造成的损害。方法以复合树脂修复后的下颌第一恒磨牙I类洞型为研究对象,采用有限元法,通过螺旋CT扫描技术建立三维有限元模型,在同一模型牙合面分别进行模拟加载,比较不同载荷情况下牙釉质、牙本质、修复体的最大Von Mises应力及最大主应力的分布情况。结果无论在垂直加载还是在侧向加载情况下,随着牙合力增大,牙釉质、牙本质、修复体的最大Von Mises应力及最大主应力值均增大。牙釉质、修复体的最大应力值明显大于牙本质的最大应力值。垂直加载情况下,牙釉质、修复体的应力较小,以压应力为主且分布均匀,而侧向加载（由舌向颊）情况下,牙釉质、修复体的应力分布不均匀,在牙釉质与修复体舌侧交界处拉应力明显增高。在修复体内,最大应力值位于修复体表面,越往下应力值越小。结论1.三维有限元分析法是一种简捷有效的生物力学分析方法;2临床上应注意修整窝洞形态及对牙合牙牙尖形态,使作用于患牙上的牙合力较小且方向尽量平行于牙体长轴。提高复合树脂与牙釉质的粘结强度可以大大降低复合树脂修复的失败率。

THREE-DIMENSIONAL FINITE ELEMENT ANALYSIS OF THE CLASSⅠCAVITY RESTORED BY COMPOSITE RESIN

Objective Quantitatively studied the effect of power and distribution of tooth tissue and dental prosthetic restoration stress by jaw force factors in different jaw force after restored by composite resin and analyzed the possible damage of tooth tissue and dental prosthetic restoration caused by them.Methods The first permanent mandible molar that was restored by composite resin chosen to the study and the finite element analysis was used.Establishing three-dimensional finite element model by spiral computed tomography and gave stimulant loading in occlusalf surface at the same model.The maximum Von Mises stress and maximum main stress distribution of adamantine layer,dentin,and dental prosthetic restoration in different load were compared.Results With the jaw force increased,the maximum Von Mises stress and Maximum main stress of enamel,dentine and dental prosthetic restoration was increased whatever loaded at vertical or lateral direction.The maximum main stress value of enamel,and dental prosthetic restoration were more than dentine obviously.In the situation of loaded at vertical direction,the stress of enamel,and dental prosthetic restoration was lower,but the stress of enamel,and dental prosthetic restoration distributed uneven in the situation of loaded at lateral direction and tensile stress increased obviously at borderline between enamel and dental prosthetic restoration in tongue side.In dental prosthetic restoration,the Maximum stress laid the surface of dental prosthetic restoration and decreased at lower place.Conclusion 1.The Finite Element Method is a simple and effective biomechanics analysis methods.2.It should be paid more attention on repairing cavity and jaw dental cusp and the jaw force on the bad tooth should lower and parallel long axis of tooth.Improving sticking intension between composite resin and enamel can decrease fail rate of composite resin restoring.