Biomechanical comparison between the custom-made mandibular condyle prosthesis and total temporomandibular joint prosthesis in finite element analysis

Purpose: The purpose of this study was to compare the biomechanical behavior of the custom-made mandibular condyle prosthesis and total TMJ prosthesis. Methods: Three models of one beagle dog, the condyle prosthesis (Model 1, replacing the right condyle only), the TMJ prosthesis (model 2, replacing the whole right TMJ) and the intact TMJ (model 3) were established, and the mechanical responses under muscle forces loading were analyzed using finite element method. Results: Models 1 and 3 had the similar stress distribution on the right disc, which suggested that the condyle prosthesis did not change the disc stress so much when the muscle forces were applied. The stress of the right TMJ prosthesis in Model 2 was larger than both Models 1 and 3, and the stress of the contralateral TMJ reduced by 12% in Model 2. The anterior border of the condyle seemed to be a stress concentration region, not only for the intact condyle, but also for the condyle prosthesis and the total TMJ prosthesis. Conclusions: The total TMJ prosthesis changed the biomechanical balance of the bilateral TMJ. When the condyle prosthesis iss applied, the custom-made profile is recommended.