Department of Oral Sciences, Second University of Naples, Naples, Italy.
J Adhes Dent. 2010 Oct;12(5):403-13. doi: 10.3290/j.jad.a18394.
To assess under load the biomechanical behavior of the cementing system of feldspathic vs alumina porcelain veneers.
A 3D model of a maxillary central incisor, the periodontal ligament (PDL) and the alveolar bone was generated. Incisors restored with alumina and feldspathic porcelain veneers were compared to a natural sound tooth. Enamel, cementum, cancellous and cortical bone were considered isotropic elastic materials; conversely, dentin was designated as orthotropic. The nonlinear visco-elatic behavior of the PDL was considered. The adhesive layers were modelled using spring elements. A 50-N load at a 60-degree angle to the tooth's longitudinal axis was applied and validated. Stress concentration in the interfacial volumes of the main models was identified and submodelled in a new environment.
Regarding tooth structure, strain concentrations were observed in the root dentin below the CEJ. As to the cement layer, tensile stresses concentrated in the palatal margin of the adhesive complex.
Despite the effects on tooth deformation, the rigidity of the veneer did not affect the stress distributions in the cement layer or in the adhesive layers. In both cases, the palatal and cervical margins seemed to be the most stressed areas.
评估长石瓷和氧化铝瓷贴面的粘结系统在负载下的生物力学行为。
生成了上颌中切牙、牙周膜（PDL）和牙槽骨的 3D 模型。比较了用氧化铝和长石瓷贴面修复的切牙与天然健康牙齿。釉质、牙骨质、松质骨和皮质骨被认为是各向同性弹性材料；相反，牙本质被指定为各向异性。考虑了 PDL 的非线性黏弹性行为。使用弹簧元件对粘结层进行建模。在与牙齿纵轴成 60 度角的位置施加 50-N 的负载，并进行了验证。在主要模型的界面体积中识别出应力集中，并在新环境中进行了子模型化。
关于牙齿结构，在 CEJ 以下的牙根牙本质中观察到应变集中。至于粘结层，拉伸应力集中在粘结复合体的腭侧边缘。
尽管对牙齿变形有影响，但贴面的刚性并不影响粘结层或粘结层中的应力分布。在这两种情况下，腭侧和颈侧边缘似乎是受力最大的区域。
