Simulations And Mechanism Research On Impact Injure To The Human Mandible By Finite Element Method

Craniofacial area is a part of the body exposed,and is highly susceptible to be damaged in wartime and difficult to be protected.Impact injury accounte for about 85% of trauma in craniofacial area in peacetime.The mandible is more vulnerable to damaged,which is the prominent area and the only movable bone in the craniofacial area.Therefore,the research on impact injury of mandible in craniofacial area is always the hotspot in the field of trauma.Animal or cadaver were used to be the model of traditional research on impact injury,however,these models are time consuming and ethics restrictions in additional to differences between the human body and animal in craniofacial structures.At the same time,the mechanical properties of the corps,which was soaked for a long time,are also different from the normal human body,thus,there are many limitations in application of the traditional models.Finite Element Method(FEM)is a method that the complex mechanical problem of the whole model can been divided into a finite number of units that interconnected and the mechanical characteristics of unit are analyzed,FE model can be repeated in different conditions of simulation,structural changes and stress and strain distributions of various parts of model under different mechanical loading conditions were intuitive presented,and the various tissue mechanical parameters what we need are output.In recent years,with the development of computer technology,FEM has been applied for the study of oral biomechanics research,for example,study the changes of biomechanical of the jaw and the mechanical of the adjacent bones when various kinds of trauma occurred in filed of oral biomechanics,with the advantages of low cost,conditions of experiment easy be controlled,experiments can be repeated,and not subject to the limitation of ethics.However,we have little know about using FEM to anlaysis the mechanical characteristics of the impact injury in craniofiacial areaIn this study,a high emulational three-dimensional(3D)FE models of human craniofacial bone for impact injuries were establised and dynamical simulations of the process of different impact forces to the human mandible were carried out by using these models with FE software.Aferwards,the mechanism of impact injuries in craniofacial area was studied based on the simulation results of forms of bone injury and changes of biomechanical,Methods:To investigate Using Mimics,Hypermesh software to build a finite element model of human craniofacial bone based on CT scan data of normal adult maxillofacial.Using LS-DYNA software to simulate each impactor with different quality,different velocity,different angles injures human mandible,then analysising Von Mises stress changes and morphology of bone injury of mandible in the process of impact injury.Results:1.A finite element model of human maxillofacial bone model was established,in the form of surface grid,the number of the elements and node were 801604 and 400257,the model was similar to its anatomical structure and the mesh quality was high.2.A high emulational 3D finite model of craniofacial bones was constructed successfully,as a part,mandibular model was established in the form of body grid and cranial maxillary complex model was established in the form of surface grid,the number of the elements were 27552 and 643031.The two parts were combined basing on the anatomical characteristics of the temporomandibular joint(TMJ).3.The dynamic process of different impact force to the model was successfully simulated,and the model could meet the demand of research for impact injury in mandibular..4.Stress transfering to the surrounding bone from the impact position radially.Mandibular chin and condylar neck were the stress concentration areas in the process of mandible injury,and these area were also serious damaged areas.Conclusions:The procedure of impact force to the mandible could be simulated by the finite element model successfully.Stress transfered to the surrounding bone from the impact position radially,gradually reduced meanwhile,small cross-section parts prone to high stress area.The quality,the velocity,the impact angle,together with the impact sites were the key factors affecting the severity of impact injury.