Faculty of Infrastructure Engineering, Dalian University of Technology, Dalian, China.
Dental Materials Science, Umeå University, Umeå, Sweden.
Int J Numer Method Biomed Eng. 2022 Mar;38(3):e3561. doi: 10.1002/cnm.3561. Epub 2021 Dec 16.
A series of three-dimensional (3D) numerical simulations are conducted to investigate the gradual failure process of molars in this study. The real morphology and internal mesoscopic structure of a whole tooth are implemented into the numerical simulations through computerized tomography scanning, digital image processing, and 3D matrix mapping. The failure process of the whole tooth subject to compressions including crack initiation, crack propagation, and final failure pattern is reproduced using 3D realistic failure process analysis (RFPA3D) method. It is concluded that a series of microcracks are gradually initiated, nucleated, and subsequently interconnect to form macroscopic cracks when the teeth are under over-compressions. The propagation of the macroscopic cracks results in the formation of fracture surfaces and penetrating cracks, which are essential signs and manifestations of the tooth failure. Moreover, the simulations reveal that, the material heterogeneity is a critical factor that affects the mechanical properties and fracture modes of the teeth, which vary from crown fractures to crown-root fractures and root fractures depending on different homogeneity indices.
本研究通过计算机断层扫描、数字图像处理和 3D 矩阵映射，将真实的牙齿形态和内部介观结构纳入数值模拟中。采用 3D 真实现实破坏过程分析（RFPA3D）方法再现了整个牙齿在压缩作用下的破坏过程，包括裂纹萌生、扩展和最终破坏模式。研究结论表明，当牙齿受到过压缩时，会逐渐产生一系列微裂纹，这些微裂纹会萌生、扩展并相互连接，形成宏观裂纹。宏观裂纹的扩展导致了断裂表面和穿透裂纹的形成，这是牙齿失效的重要标志和表现。此外，模拟结果表明，材料的非均质性是影响牙齿力学性能和破坏模式的关键因素，根据不同的均质性指数，牙齿的破坏模式从冠部断裂到冠根断裂和根断裂不等。
