Six patients had osseous destructive changes of the temporomandibular joint after placement of Teflon-Proplast implants for treatment of internal derangements. The implants were surgically removed from all six joints, and foreign-body reactions were found to account for the radiographic appearance. The plain film radiographic features included single or multiple osseous erosions of the mandibular condyle in all cases and the temporal bone of the glenoid fossa in two cases. Some erosions were poorly defined, whereas others were well defined, either with or without sclerotic margins. Radiologists must be aware of this possible complication of alloplastic temporomandibular joint implants in order to suggest the diagnosis in the appropriate clinical setting.