PDL soft tissue material is sandwic

PDL soft tissue material is sandwiched between teeth and alveolar bone, and the mechanical properties of these three materials are very different. Teeth and alveolar bones are hard tissues, which can be simulated using linear elastic materials,while PDL is an incompressible visco-hyperelastic material that will produce volume locks when numerically simulated[2, 14]. In previous papers, teeth and alveolar bones were assumed as rigid bodies [12, 15]. Such an assumption is reasonable basing on the fact that the elastic modulus of tee this much larger than PDL [16]. However, in order to provide a more accurate simulation and provide a better theoretical basis for dental bone reconstruction, this article considers teeth and alveolar bone as elastomers. For such a complex multi-materials structure with incompressible properties, the result of simulation using only one linear element in commercial software will be inaccurate [17, 18], and the use of higher-order elements makes pre-processing and computation a very time-consuming task because of the complexity of the structure [19]. Therefore, the smoothed finite element using linear elements is a very good alternative.