A STUDY OF THE CONTROL OF DISC MOVEMENT WITHIN THE TEMPOROMANDIBULAR-JOINT USING THE FINITE-ELEMENT TECHNIQUE

Purpose: A two-dimensional finite element model was developed to simul ate and study the in vivo biomechanics and mechanisms of the human tem peromandibular joint (TMJ) over the range of normal motion. Materials and Methods: A nonlinear model was developed and run using the commerc ially available ABAQUS software with slide line elements that allowed large displacements and arbitrary contact of surfaces, The three main components of the model were the mandibular condyle, articular disc, a nd glenoid fossa region of the temporal bone, which were all modeled a s deformable bodies. Continuous motion was simulated by doing a static analysis for each of many small steps, A parametric study was perform ed by determining the maximum stress in each of the three main compone nts as a function of the elasticity of the articular disc, Results: Th e articular disc was found to move along with condyle in a lifelike ma nner, even when there were no attachments to the disc, Stress distribu tion plots showed relatively high stresses deep in the glenoid fossa f or most steps, There was a direct, although nonlinear, relationship be tween maximum stress for all three components and the stiffness of the disc. Conclusions: This model suggests that muscle contraction is not required to maintain proper disc position, Normal motion results in r elatively high stresses deep in the glenoid fossa, The elasticity of t he in vivo articular disc may be closer to the lower end of the report ed values.