Histological findings in soft tissues around temporomandibular joint prostheses after up to eight years of function

Early temporomandibular joint (TMJ) prostheses articulated on material with poor wear resistance. Wear debris was deposited in the surrounding tissues, causing severe foreign body cell reactions. Recent TMJ prostheses use modern orthopaedic materials, such as ultra high molecular weight polyethylene (UHMWPE) for the fossa component, and cobalt-chromium, or cobalt-chromium-molybdenum for the condylar head. These designs are reliable in long-term follow-up studies. The authors report histological findings in soft tissue samples obtained from around two types of TMJ prostheses after up to 8 years of function. The devices were four Biomet (Biomet Microfixation, Jacksonville, FL, USA), and two TMJ Concepts (TMJ Concepts, Ventura, CA, USA). All joint capsule samples demonstrated dense, fibrous connective tissue with no inflammatory cells or foreign body reactions. The joint disc tissues showed even denser fibrous connective tissue, free from inflammatory reactions. Some samples from the junction between capsule and disk demonstrated synovial-like tissue. The observations reported in this paper indicate that modern TMJ prostheses with Cr-Co-Mb or Cr-Co articular condyles articulating on UHMWPE fossa components appear to function without foreign body reactions in he surrounding tissues.