Department of Restorative Sciences, Herman Ostrow School of Dentistry of USC, University of Southern California, 3151 S. Hoover St., Los Angeles, CA 90089-7792, USA.
Dent Mater. 2012 Jul;28(7):777-82. doi: 10.1016/j.dental.2012.04.002. Epub 2012 May 9.
The purpose of this investigation was to compare stresses within bonded porcelain and composite resin ultra-thin occlusal veneers to restore advanced erosive lesions.
A sound maxillary molar was digitized with a micro-CT scanner. The 2D image data were converted in a 3D model using an interactive medical image processing software (Mimics). Standard triangle language files (STL files) of enamel and dentin surfaces were then exported to the software 3-matic to execute design and meshing operations. Solid 3-dimensional (3-D) models acquired in a finite element software (Marc/Mentat) were subjected to nonlinear contact analysis to simulate occlusal loading at 200N and 800N. Values of maximum principal stress and ultimate tensile strength were used to calculate the risk of fracture and for validation with existing experimental data.
There were marked differences in stress distributions both at 200N (maximum peak values of 21.59, 28.63, 31.04MPa) and 800N (96.16, 115.73, 134.90MPa) for all restorative materials (MZ100, Empress CAD and e.max CAD, respectively). High tensile stresses (measured in the central groove) were found at 800N with the ceramic occlusal veneers showing occlusal stress peaks 17-29% higher than composite resin. The estimated risk of fracture was decreased for ultrathin composite resin occlusal veneers, which correlated with the existing validation data.
Ultra-thin composite resin (MZ100) and lithium disilicate (e.max CAD) occlusal veneers represent a conservative alternative to traditional onlays and complete coverage crowns for the treatment of severe erosive lesions in the posterior dentition.
本研究旨在比较修复重度牙酸蚀症的复合树脂超薄贴面和全瓷贴面的粘结瓷内的应力。
使用微 CT 扫描仪对一颗健康的上颌磨牙进行数字化扫描。使用交互式医学图像处理软件（Mimics）将二维图像数据转换为三维模型。然后，将釉质和牙本质表面的标准三角语言文件（STL 文件）导出到软件 3-matic 中，以执行设计和网格操作。在有限元软件（Marc/Mentat）中获取的三维实体模型进行非线性接触分析，以模拟 200N 和 800N 的咬合加载。使用最大主应力和极限拉伸强度值来计算骨折风险，并与现有实验数据进行验证。
在 200N（最大峰值分别为 21.59、28.63、31.04MPa）和 800N（96.16、115.73、134.90MPa）时，所有修复材料（MZ100、Empress CAD 和 e.max CAD）的应力分布均有明显差异。在陶瓷贴面中，在 800N 时发现了高拉伸应力（在中央凹槽中测量），其牙合向应力峰值比复合树脂高 17-29%。超薄复合树脂牙合贴面的骨折风险估计降低，与现有验证数据相关。
超薄复合树脂（MZ100）和锂硅瓷（e.max CAD）贴面是治疗后牙重度牙酸蚀症的传统高嵌体和全冠的保守替代方案。
