Effects of occlusal loads on the stress distributions in temporomandibular joint

The stress distributions of the temporomandibular joint (TMJ) under centric occlusion, anterior occlusion and unilateral occlusion were analyzed. A three-dimensional finite element model of the TMJ with mandible and teeth was developed according to CT images of a volunteer with asymptomatic joints. Contact elements were used to simulate the interaction between the articular discs and the mandibular condyles and between the articular discs and the articular fossas. The muscle forces and boundary conditions corresponding to the three occlusions were applied on the model. It was observed that the stresses of the TMJs in the models with anterior occlusion and unilateral occlusion are higher than those in the model with centric occlusion. In the three models, the maximum and minimum stresses of the discs occur in the intermediate zones and the anterior bands, respectively. Moreover, the stresses on the ventral disc are higher than the dorsal disc. The high stresses of the discs are located at the intermediate zones under the three occlusions. The stress of the contralateral TMJ is much higher than the ipsilateral TMJ under the unilateral occlusion.