Finite Element Analysis of TMJ Implant

The TMJ is a bilateral joint of the jaw that functions as a single entity during normal masticatory activities, speaking, yawning and swallowing. TMJ replacement has been indicated in cases of joint trauma, advanced degenerative disease, tumors, developmental anomalies and ankylosis of the joint following injury. Alloplastic replacement of the TMJ (an artificial replacement in the form of a TMJ condylar implant with a glenoid fossa component that articulates with the undersurface of the skull on the temporal bone) renders the anatomical space devoid of the natural mandibular condyle (Fig. 1). Compared to hip and knee prostheses, TMJ implants have not been studied in detail. The goals of this study were to quantify the stress distribution in a commercially available TMJ implant (TMJ Implants, Inc, CO), bone and implant-bone interface, to compare the stresses and strains with different bone conditions, and to compare the stresses and strains with different implant materials using a finite element software package.