Page 70 - Demo

Chapter 368hand, consists solely of UHMWPE, without a metal support. For early implants, any surface roughness in the fossa was leveled using PMMA cement, but this was abandoned later because of the risk of fragmentation of PMMA under functional loading.(6) Both components are fixated using self-tapping screws made of Ti6Al-4V.(7,8,36,39)The TMJ Concepts system was introduced in 1989 as a Techmedica system, however the FDA halted the manufacturing of custom devices in 1993. In 1996, the new company TMJ Concepts, Inc., received FDA approval for their custom TMJ implant system as an investigational device, with the device becoming available for patient use in 1997. Finally in 1999 TMJ Concepts, Inc. received full FDA approval for their patient-fitted TMJ implant system. The fossa of the TMJ Concepts prosthesis is made from a commercially pure (cp) Ti mesh backing, which can be adapted to the patient’s anatomy, and four layers of cp Ti mesh, which provide stability and allow for bony ingrowth to occur. On the caudal side of the mesh backing, a UHMWPE lining functions as the articulating surface. While the ramal shaft of the Techmedica implant was made of either cp Ti or a wrought Ti6Al4Valloy, the newer TMJ Concepts, Inc. system only uses Ti-6Al-4V. Both the fossa and mandibular parts are fixated with the help of Ti6Al4Vscrews.(6,9,37,40)Considerations for temporomandibular joint total joint replacement materialsThe previous paragraphs highlighted several difficulties encountered throughout the history of the (total) TMJ prosthesis, which could often be traced back to inappropriate material selection for a given implant design, such as the use of Proplast in the Vitek-Kent system or Silastic Figure 5: TMJ Concepts Patient-Fitted Total TMJ Replacement SystemNikolas de Meurechy NW.indd 68 05-06-2024 10:14