A biomechanical evaluation of the Christensen temporomandibular joint implant.

The Christensen TMJ implant is often used clinically as a total joint replacement of the temporomandibular joint. The system consists of a thin fossa component and a condylar component with a polished articular head. In this study, we analyzed the surface finish and the metal structure of the components. We also measured the contact areas between the two components for different load levels. Such information may be useful in evaluating clinical performance as well as in making future improvements in the design of these implants.

Temporomandibular Joint Arthroplasty Using Metal-on-Metal and Acrylic-on-Metal Configurations : Wear In Laboratory Tests and In Retrievals.

In the long-term performance ofthe temporomaridibular joint (TMJ) implant, wear must be considered. Thus retrieved and laboratory test implants were examined both optically and in a scanning electron microscope (SEM). In laboratory testing, the volumetric wear of metal-on-metal was about an order of magnitude less than that of acrylic-on-metal TMJ implants. This metal-on-metal wear was also about half of that reported in the literature for a laboratory test of polyethylene-on-metal TMJ implants, The retrieved TMJ implants showed some abrasive wear occurred during multi-directional articulation with smaller wear zones for the metal-on-metal compared to the acrylic-on-metal configuration. Further efforts to characterize and minimize wear were recommended as prudent in the continuing development of TMJ arthroplasty.

Alternative Total TMJ Arthroplasty: Metal-on-Metal for Longevity in Implant Survivorship and Patient Satisfaction.

Use of biomaterials as an implant device for TMJ joint reconstruction in oral maxillofacial surgery has been an ever-increasing dilemma for the oral maxillofacial surgeon. The decision to choose the best procedure and device/material in providing longevity wirh satisfaction to the patient has become a demanding factor. Maxillofacial surgeons are faced with a "young age" patient population and are in a continual struggle to find the proper device to maintain long-term survivorship without recurrent multiple operations. This multiple operation(s) factor can cause a further complication in itself, and also reduce the survivorship of implant devices. There has been a steady decrease in recent years in the number of TMJ surgical procedures performed by accredited OMS residency training programs; this may be due to the many short-term survivorship failures with certain alloplastic devices (Proplast/Teflon and Silastic) as well as the short-term survivorship of autologous tissue implants (Fascia and Grafts) and the added factor of enhanced complications with multiple surgeries. So the question asked by many oral maxillofacial surgeons is: what other procedure or biomaterial/device, if any, is available to avert the ever-present TMJ disease process and disorder?

The Christensen prosthesis. A retrospective clinical study.

The objective of this study was to determine if the Christensen temporomandibular joint prosthesis system in an effective alternative in treating patients with severe temporomandibular joint disorders. A total of 69 patients who were not responsive to either nonsurgical or prior surgical treatments were placed into one of three treatment groups depending on the following diagnoses: (1) placement of a glenoid fossa-eminence prosthesis with meniscus retention (22 patients, 40 joints); (2) placement of a glenoid fossa-eminence prosthesis without retention of the meniscus (26 patients, 49 joints); (3) total joint replacement (21 patients, 34 joints). Patients were evaluated immediately before surgery and at regular intervals after surgery for an average of 3.1 years. Success was measured as a significant improvement of function and decrease in pain as measured on a visual analogue scale, as well as improved incisor opening as measured with a Therabite Scale (Lorenz Surgical, Jacksonville, Fla.). Comparison of mean and average pre- and postsurgical values for all groups and criteria showed significant improvement. Results of this study indicate that the Christensen temporomandibular joint prosthesis system may offer a viable method for the treatment of severe temporomandibular joint disease with a high degree of success.