Yu Shuyang, Sun Zhaohua, Ren Xuhua, Zhang Jixun, Yu Jun, Zhang Wenbing
School of Transportation and Civil Engineering, Nantong University, Nantong, 226019, China.
School of Transportation and Civil Engineering, Nantong University, Nantong, 226019, China.
J Mech Behav Biomed Mater. 2022 Dec;136:105518. doi: 10.1016/j.jmbbm.2022.105518. Epub 2022 Oct 11.
The present work aims to propose a meshless method to establish the tooth meso-structures and model the tooth fracturing processes as well as investigate the influencing factors that affect the dental mechanical properties. To this end, the traditional kernel function in the SPH method has been improved by introducing a fracture mark ξ to realize the progressive failure processes of teeth; The "Particle Searching Method" has been proposed, which can realize the establishments of microstructures of teeth such as enamel, dentine, pulp, PDL and alvedar bones. The Weibull function is introduced to represent the heterogeneity of teeth, which can realize the random distribution characteristics of dental mechanical parameters. The simulation results of homogeneous and heterogeneous teeth show that the failure mode changes from tensile splitting (homogeneous) to shear failure (heterogeneous). Meanwhile, the fracture networks become more complex, and the failure stress decreases sharply. The cuspal angles also have a great impact on the teeth fracture characteristics. The failure modes changes from tensile splitting of the enamel tip to the cracking from the contact points between the enamel and the rigid ball; Different fssural morphologies have little influences on the teeth failure characteristics. The research results can provide some references for the applications of SPH method into biomechanical simulations such as teeth failure. Meanwhile, it can also provide some guidance for the understandings of the internal mechanisms of teeth fracture processes, the diagnosis and treatments of clinical diseased teeth as well as the design of bionic teeth materials.
本工作旨在提出一种无网格方法来建立牙齿的细观结构并模拟牙齿断裂过程，以及研究影响牙齿力学性能的因素。为此，通过引入断裂标记ξ改进了光滑粒子流体动力学（SPH）方法中的传统核函数，以实现牙齿的渐进破坏过程；提出了“粒子搜索方法”，该方法可实现牙釉质、牙本质、牙髓、牙周膜和牙槽骨等牙齿微观结构的建立。引入威布尔函数来表征牙齿的非均匀性，可实现牙齿力学参数的随机分布特性。均质和非均质牙齿的模拟结果表明，破坏模式从拉伸劈裂（均质）转变为剪切破坏（非均质）。同时，断裂网络变得更加复杂，破坏应力急剧降低。牙尖角度对牙齿断裂特性也有很大影响。破坏模式从牙釉质尖端的拉伸劈裂转变为牙釉质与刚性球接触点处的开裂；不同的裂隙形态对牙齿破坏特性影响较小。研究结果可为SPH方法在牙齿破坏等生物力学模拟中的应用提供一些参考。同时，也可为理解牙齿断裂过程的内部机制、临床病牙的诊断和治疗以及仿生牙齿材料的设计提供一些指导。
