Karimi Alireza, Razaghi Reza, Biglari Hasan, Rahmati Seyed Mohammadali, Sandbothe Alix, Hasani Mojtaba
Department of Mechanical Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.
Department of Mechanical Engineering, University of Tabriz, Tabriz 51666, Iran.
Saudi Dent J. 2020 Nov;32(7):349-356. doi: 10.1016/j.sdentj.2019.10.005. Epub 2019 Nov 6.
The stresses and deformations in the periodontal ligament (PDL) under the realistic kinetic loading of the jaw system, ., chewing, are difficult to be determined numerically as the mechanical properties of the PDL is variably present in different finite element (FE) models. This study was aimed to conduct a dynamic finite element (FE) simulation to investigate the role of the PDL (PDL) material models in the induced stresses and deformations using a simplified patient-specific FE model of a human jaw system.
To do that, a realistic kinetic loading of chewing was applied to the incisor point, contralateral, and ipsilateral condyles, through the experimentally proven trajectory approach. Three different material models, including the elasto-plastic, hyperelastic, and viscoelastic, were assigned to the PDL, and the resulted stresses of the tooth FE model were computed and compared.
The results revealed the highest von Mises stress of 620.14 kPa and the lowest deformation of 0.16 mm in the PDL when using the hyperelastic model. The concentration of the stress in the elastoplastic and viscoelastic models was in the mid-root and apex of the PDL, while for the hyperelastic model, it was concentrated in the cervical margin. The highest deformation in the PDL regardless of the employed material model was located in the caudal direction of the tooth. The viscoelastic PDL absorbed the transmitted energy from the dentine and led to lower stress in the cancellous bone compared to the elastoplastic and hyperelastic material models.
These results have implications not only for understanding the stresses and deformations in the PDL under chewing but also for providing comprehensive information for the medical and biomechanical experts in regard of the role of the material models being used to address the mechanical behavior of the PDL in other components of the tooth.
由于牙周韧带（PDL）的力学性能在不同的有限元（FE）模型中存在差异，因此在颌骨系统实际动态载荷（即咀嚼）作用下，牙周韧带中的应力和变形难以通过数值方法确定。本研究旨在使用简化的特定患者人类颌骨系统有限元模型进行动态有限元（FE）模拟，以研究PDL材料模型在诱导应力和变形中的作用。
为此，通过经实验验证的轨迹方法，将实际的咀嚼动态载荷施加到切牙点、对侧和同侧髁突上。将三种不同的材料模型，包括弹塑性、超弹性和粘弹性模型，应用于PDL，并计算和比较牙齿有限元模型产生的应力。
结果显示，使用超弹性模型时，PDL中的von Mises应力最高，为620.14 kPa，变形最小，为0.16 mm。弹塑性和粘弹性模型中的应力集中在PDL的牙根中部和根尖，而超弹性模型中的应力集中在颈部边缘。无论采用何种材料模型，PDL中最大的变形都位于牙齿的尾侧方向。与弹塑性和超弹性材料模型相比，粘弹性PDL吸收了来自牙本质的传递能量，并导致松质骨中的应力降低。
这些结果不仅有助于理解咀嚼过程中PDL中的应力和变形，还为医学和生物力学专家提供了关于材料模型在牙齿其他组成部分中用于描述PDL力学行为的作用的全面信息。
