Development and clinical application of the total temporomandibular joint (T.M.J.) endoprosthesis

In the course of designing a T.M.J. endoprosthesis we performed biomechanical analysis for testing the stress relationships of the condyle. The photoelastic stress analysis showed that the compressive force in the glenoid fossa varied from 90 to 270 N. The experiments showed also that the selected shape of the prosthetic condyle absorbs the forces of the mandible in a way similar to the natural condylar process. Therefore, we developed a total T.M.J. endoprosthesis. The condyle is made of a Titanium--alloy, the socket of high density polyethylene. From 1978 to 1987 we implanted 25 endoprostheses in 18 patients. The mean age of the patients at the time of the operations was 33 years. Indications for the implantation of total T.M.J. endoprostheses in adults are ankylosis, tumours, multiple fractures and, after all possibilities of conservative treatment have been exhausted, severe deforming arthropathy.