A preliminary evaluation of the surface of surgically removed Proplast/Teflon interpositional disc implants from human temporomandibular joints

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A preliminary evaluation of the surface of surgically removed Proplast/Teflon interpositional disc implants from human temporomandibular joints
April 2005
Editor: Martin S. Greenberg
Oral Medicine
Objectives. The scientific literature has presented evidence that wear debris of temporomandibular joint (TMJ) interpositional disc (ID) implants follows implant failure and results in progressive osseous erosion of the TMJ and chronic orofacial pain. The purpose of this study is to investigate the surface structure of removed human TMJ ID implants, because wear debris appears to result from structural collapse of TMJ ID.
Methods. Four surgically retrieved Proplast/Teflon TMJ ID implants from 3 patients, who had the implants in for greater than 15 years, were previously collected through the National Institute of Dental and Craniofacial Research TMJ Implant Registry and Repository (NIDCR TIRR) and were selected for analysis. The implants, previously stripped of all patient identifiers, were stored in 10% buffered formalin or 4% paraformaldeyde immediately after surgical removal. Implants were washed thoroughly with distilled water prior to observation with a Leica S6D stereo zoom microscope (0.63?ÛǃÏ4?Û). Surface characteristics of each implant were documented using a digital camera (Leica DFC280). The number of surface perforations, position of any central perforation, and fragmentation were documented. The presence or absence of surface scratches was also noted. The characterized features were then correlated with selected deidentified clinical findings. The clinical findings from NIDCR TIRRǃÏconsenting patients was recorded 1 to 3 months prior to the implants' surgical removal.
Results. All implants were perforated with traces of surface scratch on the polymeric (Teflon) surface. The largest perforations were located near the center of the implant. TMJ ID implant failure patterns also include Teflon-layer fragmentation and detaching of the 2 layers of the implant. Severe fragmentation with fiber extrusion was observed in 2 implants. Clinical findings revealed all patients had TMJ pain on the implant side on maximum assisted jaw opening, maximum unassisted jaw opening <38 mm, and lateral excursive movement limitation towards the normal joint side. The patient who had severe fragmented implants described feelings of a foreign body migration at the joint. TMJ CT scan reports showed hypertrophic changes, flattening, bone resorption, fragmentation, subcondral cysts on the condyle, and a perforation into the medial cranial fossa. MRI evaluations showed significant osteolysis of the condylar head and severe glenoid fossa resorption, close to perforating the middle cranial fossa.
Conclusions. Polymeric breakdown particles (implant wear debris) appear to trigger a degenerative reaction resulting in pain and limitation on the dynamics of the TMJ, similar to those described in previous studies.1,2 Further analysis of an expanded sample of retrieved implants will continue and be presented at the meeting. Histopathologic and immunochemical methods to analyze these implants are under way to test this hypothesis and study underlying failure mechanisms of TMJ ID implants.
References TOP
1. Trumpy IG, Lyberg T. Temporomandibular joint dysfunction and facial pain caused by neoplasms. Report of three cases Oral Surg Oral Med Oral Path 1993;76:149-152. MEDLINE
2. Feinerman DM, Piecuch JF. Long-term retrospective analysis of twenty-three Proplast-Teflon temporomandibular joint interpositional implants Int J Oral Maxillofac Surg 1993;22:11-16. MEDLINE