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 simulate and study the in vivo biomechanics and mechanisms of the human temperomandibular joint (TMJ) over the range of normal motion.

MATERIALS AND METHODS

A nonlinear model was developed and run using the commercially 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, and glenoid fossa region of the temporal bone, which were all modeled as deformable bodies. Continuous motion was simulated by doing a static analysis for each of many small steps. A parametric study was performed by determining the maximum stress in each of the three main components as a function of the elasticity of the articular disc.

RESULTS

The articular disc was found to move along with condyle in a lifelike manner, even when there were no attachments to the disc. Stress distribution plots showed relatively high stresses deep in the glenoid fossa for most steps. There was a direct, although nonlinear, relationship between 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 relatively high stresses deep in the glenoid fossa. The elasticity of the in vivo articular disc may be closer to the lower end of the reported values.