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Chapter 246discarded these findings, claiming that the TMJ was subjected to lighter loads and would be less susceptible to fragmentation.(71) Influenced by Cook’s findings, Kent coated the articulating surface of his condylar prosthesis with Proplast in 1972. By adding a fossa component to the ramal component in 1983, due to reports showing resorption of the fossa, the infamous Vitek-Kent prosthesis was created.(18,19,36,71,74) As with Silastic, the material was also used as a replacement for the TMJ disc, which was first devised in 1976. A survey conducted by Vitek(74) showed that over 5070 patients had been treated with the interpositional implant by 1986 and Spagnoli and Kent(80) estimated that up to 20,000 disc implants were placed before the production of the prosthesis was halted. At the annual AAOMS meeting in 1986, there were several reports of implants showing biomechanical failure. Vitek, however, stated that the reported failures were due to operative technique of the surgeon rather than a flawed choice in materials.(80) As time went on, more reports were published showing far less promising results such as severe bony degeneration, FBGCR, material fragmentation, and particles found in lymph nodes near the implant site.(81–85) This led to the discontinuation of the Proplast disc replacement in 1988.(80) In the end, a study by Wagner and Mosby(22), as well as two master’s theses from the University of Iowa, led the FDA to issue a safety alert in 1990 to US oral and maxillofacial surgeons, who were asked to re-examine all patients treated with Proplast or Teflon.(74) Wagner and Mosby found that 19 out of 20 patients treated with a Proplast-Teflon TMJ disc experienced severe pain, 14 patients showed a restricted maximum inter-incisal opening, and all patients showed radiological degeneration of the condyle. The authors concluded that this degeneration was caused by a FBGCR to the debris that was formed as the material wore down.(22)In an attempt to salvage the TMJ TJR system, the outer Teflon layer was replaced by a UHMWPE layer, but Proplast also became recognized for its non-compatible properties and its accompanying signs of wear, fracture lines, and fractures.(54,71,80) A study by Spagnoli and Kent(80) concluded that up to 54% of all Vitek-Kent implants included in the study might fail, with the implant system having an average in vivo lifespan of Nikolas de Meurechy NW.indd 46 05-06-2024 10:14