Research On Finite Element Modeling And Simulation Of Orthodontic Tooth Movement

With the application of finite element method,a personalized numerical simulation model can be established to study orthodontic tooth movement.Accurate finite element modeling can improve the reliability of finite element analysis results,help orthodontists to determine the best orthodontic scheme,and then shorten the orthodontic tooth treatment cycle and improve the efficiency of orthodontic treatment.In this paper,according to the CT images of human mandible,the numerical simulation model of orthodontic teeth and periodontal tissue is established,and an in-depth study is carried out on this basis.The specific research contents and results are as follows:(1)According to the CT images,the three-dimensional model of tooth-periodontic-membrane-alveolar bone was established by using Mimics,Geomagic and UG software,which was consistent with the real situation,and the three-dimensional model of simple tooth hoop was designed and drawn.The three-dimensional models of tooth hoop,tooth and periodontal tissue were imported into Abaqus respectively,and the three-dimensional finite element model of orthodontic tooth movement was established.(2)A modeling method of delamination periodontal membrane materials was proposed.Considering the different characteristics of periodontal ligament in different horizontal directions,as well as the nonlinear material properties,two kinds of periodontal ligament material models of hyperelastic zoning and hyper-viscoelastic delamination were established to study the mechanical response of periodontal ligament under different material models.The result shows that under the same orthodontic conditions,the stress distribution of the two models is roughly the same,but the stress value under the hyper-viscoelastic delamination periodontal ligament model is lower.In the finite element modeling of periodontal ligament,the hyper-viscoelastic delamination ma terial model is more reliable.(3)The process of bone remodeling was simulated.The essence of long-term slow movement of orthodontic teeth is the remodeling of alveolar bone,so it is particularly important to simulate the process of bone remodeling by finite element method.In this study,through the secondary development of Abaqus subroutine,the tooth-alveolar bone contact model was established,and the bone remodeling process was simulated.The research shows that the displacement of the alveolar bone boundary is smaller in the model considering the bone remodeling process,which is more consistent with the actual slow bone remodeling process.(4)The position of the resistance center of the tooth is solved and verified.The tooth resistance center is regarded as the basic reference point that can predict the tooth movement.In clinical orthodontics,the orthodontic scheme is often adjusted according to the position relationship between the force vector and this point.The research shows that the position of the tooth resistance center is not unique,but the proposed solution method can quickly determine the approximate position of the tooth resistance center,and then judge the type of tooth movement.In this paper,the influence of periodontal membrane material modeling method on the stress response of periodontal membrane was studied and analyzed.It was found that the layered hyper-viscoelastic periodontal ligament model was more reliable and provided a reference for accurate periodontal membrane modeling.Through the secondary development of UINTER,UVARM,and UMESHMOTION subroutines,the periodontal membrane contact model was established,and the simulation of bone reconstruction process was realized,providing a reference for the follow-up long-term orthodontic tooth movement research.Based on the analysis results of finite element software,this paper solves the resistance center,which will help to determine the type of tooth movement.