The Effects of Unilateral Alloplastic Temporomandibular Joint Replacement on the Opposite-Side Natural Joint: A Finite-Element Analysis.

PURPOSE: The purpose of this study was to evaluate the stress distribution on the temporomandibular joint (TMJ) prosthesis and contralateral natural TMJ with finite-element analysis.

MATERIALS AND METHODS: A TMJ implant was used to create a 3-dimensional model with a computer. This model was integrated with a mandible model created with a computer by use of computed tomography images, similar to a real TMJ replacement procedure. Masticatory loads were applied to the model. The loads transmitted to the TMJ prosthesis and contralateral healthy joint were evaluated by means of finite-element analysis.

RESULTS: In the model without the TMJ prosthesis, maximum von Mises stress was 252.697 N/mm2 at the condyle and 5.418 N/mm2 at the disc. In the model with the unilateral TMJ prosthesis, maximum stress at the joint prosthesis was 792.681 N/mm2 . In the contralateral natural joint, maximum stress was 268.908 N/mm2 at the condyle and 8.357 N/mm2 at the disc.

CONCLUSIONS: In the TMJ model with the unilateral total TMJ prosthesis, increased stress values were observed at the disc and condyle of the contralateral natural TMJ.