EVALUATION OF TEMPOROMANDIBULAR-JOINT PROSTHESES - REVIEW OF THE LITERATURE FROM 1946 TO 1994 AND IMPLICATIONS FOR FUTURE PROSTHESIS DESIGNS

Purpose: This article describes the useful elements of applied temporo mandibular joint (TMJ) prostheses and discusses the factors necessary to be addressed in an appropriate TMJ prosthesis design. Materials and Methods: Information about TMJ prostheses was gathered by a literatur e search, Only designs with the primary intention of true joint replac ement were selected. The designs were divided in fossa-eminence, condy lar, and total joint replacements, which are reviewed separately. Resu lts: A fossa-eminence prosthesis can be fixed by a metal plate screwed to the root of the zygomatic arch, A condylar prosthesis can be fixed by a metal plate screwed to the mandibular ramus and fitted by bendin g the plate or using different sizes. All reviewed designs resulted in a loss of translational movements of the mandible, especially in an a nterior direction, Although the recent designs use the same materials as are used in hip and knee joint prostheses, the wear properties of t he existing TMJ prostheses are still unknown. Conclusions: A future pr osthesis must imitate the anterior movement of the mandible when the m outh is opened and also allow some mediolateral movement, The fitting to the skull is still a major problem, as is the combination of the re quired motions and low wear rates. To confirm good clinical performanc e of a new TMJ prosthesis, long-term follow-up studies are necessary.