In orthodontic treatments, mechanical characterization of orthodontic bracket bonded to the tooth is essential to determine the bond strength and mechanical behavior of the bracket-adhesive-tooth system. In this study, the linear-nonlinear mechanical behavior and damage characterization of Filtek Z350 XT (3M ESPE) nanocomposite as a dental adhesive material to bond orthodontic brackets to tooth enamel, are investigated using numerical and experimental methods. Full sets of tensile, shear, and mixed modes I/II and I/II/III debonding experiments are conducted to extract the mechanical properties of the nanocomposite adhesive as the bracket/tooth interface. The results of the experiments are used to obtain the cohesive law and the damage model parameters. Three-dimensional finite element models of the bracket debonding tests are developed, while the cohesive zone model (CZM) is used to define the constitutive behavior of the nanocomposite interface under the tensile, shear, and mixed-mode loading conditions. The FE results showed a good correlation with the measured data, indicated the validity of the constitutive model, damage properties, and simulation process. The bond strengths of the nanocomposite adhesive are obtained 8.35 and 4.12MPa in modes I and II loadings, respectively.

在正畸治疗中，正畸托槽与牙齿粘合的机械特性对于确定托槽-粘合剂-牙齿系统的粘合强度和机械性能至关重要。在这项研究中，使用数值和实验方法研究了 Filtek Z350 XT (3M ESPE) 纳米复合材料作为将正畸托槽粘合到牙釉质的牙科粘合剂材料的线性-非线性力学行为和损伤表征。进行了全套拉伸、剪切和混合模式 I/II 和 I/II/III 剥离实验，以提取纳米复合粘合剂作为托槽/牙齿界面的力学性能。实验结果用于获得内聚律和损伤模型参数。开发了支架剥离试验的三维有限元模型，而内聚区模型（CZM）用于定义纳米复合材料界面在拉伸、剪切和混合模式加载条件下的本构行为。有限元结果与实测数据显示出良好的相关性，表明本构模型、损伤特性和模拟过程的有效性。在模式 I 和 II 载荷下，纳米复合粘合剂的粘合强度分别为 8.35 和 4.12MPa。