Department of Restorative Dentistry, School of Dentistry, University of Naples Federico II, V.S. Pansini 5, 80131 Naples, Italy.
Dent Mater. 2011 May;27(5):423-30. doi: 10.1016/j.dental.2010.12.001. Epub 2011 Jan 11.
In restored teeth, stresses at the tooth-restoration interface during masticatory processes may fracture the teeth or the restoration and cracks may grow and propagate. The aim was to apply numerical methodologies to simulate the behavior of a restored tooth and to evaluate fatigue lifetimes before crack failure.
Using a CAD-FEM procedure and fatigue mechanic laws, the fatigue damage of a restored molar was numerically estimated. Tessellated surfaces of enamel and dentin were extracted by applying segmentation and classification algorithms, to sets of 2D image data. A user-friendly GUI, which enables selection and visualization of 3D tessellated surfaces, was developed in a MatLab(®) environment. The tooth-boundary surfaces of enamel and dentin were then created by sweeping operations through cross-sections. A class II MOD cavity preparation was then added into the 3D model and tetrahedral mesh elements were generated. Fatigue simulation was performed by combining a preliminary static FEA simulation with classical fatigue mechanical laws.
Regions with the shortest fatigue-life were located around the fillets of the class II MOD cavity, where the static stress was highest.
The described method can be successfully adopted to generate detailed 3D-FE models of molar teeth, with different cavities and restorative materials. This method could be quickly implemented for other dental or biomechanical applications.
在修复后的牙齿中，咀嚼过程中牙-修复体界面处的应力可能会导致牙齿或修复体断裂，并且可能会产生和扩展裂纹。本研究旨在应用数值方法模拟修复后牙齿的行为，并评估裂纹失效前的疲劳寿命。
使用 CAD-FEM 程序和疲劳力学定律，对修复后的磨牙进行了数值估计疲劳损伤。通过应用分割和分类算法，从二维图像数据集提取出釉质和牙本质的镶嵌表面。在 MatLab(®)环境中开发了一个用户友好的图形用户界面，该界面允许选择和可视化三维镶嵌表面。然后通过横截面的扫掠操作创建牙釉质和牙本质的牙齿边界表面。然后在三维模型中添加 II 类 MOD 腔预备，并生成四面体网格元素。通过将初步的静态有限元分析与经典疲劳力学定律相结合来进行疲劳模拟。
最短疲劳寿命的区域位于 II 类 MOD 腔的圆角处，静态应力最高。
所描述的方法可以成功地应用于生成具有不同腔体和修复材料的磨牙的详细三维有限元模型。该方法可以快速应用于其他牙科或生物力学应用。
