Analysis On Jaw Movement And Biomechanics Of Oral With Dental Implant

Dental implant can noticeably improve chewing function of the patients and yield desirable feeling,just like the real teeth,and therefore has been extensively used in prosthodontics.With the development of dental implant technique,study of dental biomechanics becomes the key point in this research field.Because of the advantages of non-invasive,efficiency,repeatability and viewing stress in any portion,finite element method is widely used to analyze the biomechanical characteristic of dental implants.However,extracting the periodontal ligament from the whole structure is difficult to implement,hence the great majority of finite element models generally neglect the role of soft tissue.Furthermore,boundary conditions of finite element model are regularly simplified due to the complexity of mandibular movement,which has a significant effect on reliability of simulation results.By summarizing previous research results of biomechanical properties of dental implant,it is indicated that model,material property,boundary condition are key factors influencing the accuracy of finite element analysis results.This work aims to study the impact of periodontal ligament and boundary conditions on finite element analysis results.Whole model which is not segmented is constructed from the computed tomography scan images using reverse engineering software.Models of cortical bone,cancellous bone,dentition and soft tissue are generated by surface and polygon processing functions.The integrated mandibule model is thereby obtained,which is the foundation of establishing a complete and effective three-dimensional finite element model of dental implant.The trajectories of condyle center point during maximum vertical opening and closing movement of mandible is acquired using the motion measurement setup.By analyzing the experimental data,the motion form of condyle is obtained,which is formed by the combination of rotation and translation instead of a fixed-axis rotation.Through numerical analysis of mandibular movement to deduce the trajectory of incision inferius,it is found that the mandible is not a rigid body during the moving,which means that the derivation is not appropriate.In addition,with respect to the theoretical study of motion,the boundary conditions in accordance with practical situation can be set in finite element models.Compared the boundary conditions in previous literature,the influence of proposed boundary conditions on simulation results is investigated.The results show that boundary conditions have significant effect on stress distribution of mandible and the location of maximum stress.Furthermore,the impact of periodontal ligament on biomechanics of dental implant is explored.The results indicated that the periodontal ligament have barely influence on the stress distribution of alveolar bone and other parts of mandible.However,the magnitude of maximum stress on the interface is decreased by 42.96%and that on alveolar bone decreases 29.03%～52.20%,which means that periodontal ligament can reduce the stress delivered to alveolar bone.Additionally,the effect of boundary conditions on the model with dental implant is consistent with that on the model without dental implant.Therefore,periodontal ligament and boundary conditions should be considered in finite element modeling to improve the precision of model and the reliability of results.