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The dental system exposed parts of the body, regardless of peace or war, are vulnerable to injury, dental trauma research has important clinical and military significance. Maxillofacial complex anatomical structures, traditional research methods, such as cadaver experiments, animal experiments or physical model experiments, often time-consuming, laborious, and the experimental conditions is difficult to completely duplication and stability control, affect the results of reliability. With the extensive application of modern mathematical methods and computer technology in the field of medical research, there are many new simple and effective research methods, finite element analysis (FEA) is a good combination of physical and computer mathematical model of a typical representative. In this study, a brief review of injury characteristics of the temporomandibular joint (TMJ), TMJ bio-mechanics, finite element method (FEM) modeling and its research progress. CT, MR TLC scanning and Matlab software, Ansys three-dimensional finite element-specific software technology, more precise, more widely used three-dimensional finite element model of TMJ, and in the success of a model based on the mandible external force by the moment when the impact of temporomandibular joint. This experiment five different mouth bit (closed position, 1cm, 2cm, 3cm, 4cm mouth bit) contains the TMJ figures of the mandible and dentition model, and different organizations independently, given the appropriate mechanical parameters, including compact bone, cancellous bone, teeth, articular disc, articular cartilage; design constraints, the models are equipped with the top of the glenoid fossa displacement 0, increase in mandibular teeth in the closed position of the occlusal plane displacement 0 in the model of geometric similarity and biomechanical similarity on both the increased proximity with the real situation. Model of five different mouth opening in the left mandibular angle subjected to external force perpendicular to the Frankfort plane and point directly to the TMJ 1000N for bilateral TMJ articular disc and condyle average principal stress (EQV stress), by comparing Different Mouth Openings EQV stress peak size and the site, the results: (1) closed position, the the bilateral articular disc and condyle EQV stress peak are significantly smaller; (2) in the mouth bit, EQV stress peak of the articular disc located in the rear with the condylar cartilage located in the anterior slope; (3) articular disc EQV stress peak is always the left is greater than the right side of the condylar cartilage in the closed position, 1cm, 4cm mouth bit left side EQV stress peak is greater than the right, 2cm, 3cm mouth bit is the right side than the left; (4) bilateral articular disc and condylar cartilage EQV stress peak parts of the basic symmetry. Articular disc and condyle model of five different mouth opening chin in the middle sagittal plane were treated with three different directions perpendicular to the plane of Frankfort, 60o angle, parallel 1000N pressure, access to TMJ (left) condylar cartilage EQV stress peak size and the emergence of the site, to get results: (1) direction of force, different mouth opening, the articular disc EQV stress peak located after the belt, the condylar cartilage located in the anterior slope; (2) direction of force contrast, the peak force parallel to the articular disc and condyle EQV stress is significantly larger; (3) the closed position, the force in three directions TMJ EQV stress peak are significantly smaller. Model design method used in this experiment can be truly representative of the original object, the geometric shape realistic anatomical structure distinguished jaw uvula, mental foramen, and rebuild the joint area of ??high-precision three-dimensional image. Biomechanical study of the TMJ in the body, physical or mechanical model experiments, the measurement accuracy is low, the model is an oversimplification, one can do static analysis, three-dimensional finite element model established in this experiment is a breakthrough these limitations. Model the organizational structure of the different mechanical properties are independent of each other, and you can experiment the specific needs of the individual organization or structure of the deletion or re-add, not only improves the accuracy of the experiment, and to meet the different experimental requirements, the TMJ micro structure mechanical analysis accuracy is greatly improved, the respective mechanical parameters given different organizations, we get close to the mechanical and clinical practice analysis provides a new way for TMJ and mandibular biomechanical study. In addition, the experimental studies is a one-time violent TMJ patients at the moment of injured mouth opening can not be determined, we broke down the 5 different mouth opening, consider the possibility of a different state of trauma, the total damage trends summarized, reducing the difference of the experimental conditions and the actual situation, to reduce the omission, as fully as possible reflect the mechanical characteristics of the TMJ trauma.
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