The effect of Silastic replacement following discectomy in sheep temporomandibular joints.

The effect of Silastic (Dow Corning, Midland, MI) replacement following discectomy was examined in sheep temporomandibular joints (TMJs). Four sheep had disc perforations created bilaterally, and 20 weeks later the right disc was removed and replaced with a Silastic sheet. At 40 weeks following commencement of the study, the sheep were killed and the TMJs examined radiologically and histologically. The TMJs of two unoperated sheep were similarly evaluated to determine normal findings. Radiologic examination showed destructive bony change in all four operated joints. Histologic examination confirmed these bony changes in both the temporal bone and condyle. There were foreign particles with an accompanying foreign-body reaction throughout the fibrous tissue capsule that had formed around the implant.