Light and electron microscopic evaluation of Proplast II TMJ disc implants.

Proplast II disc implants (Vitek Inc, Houston) were used in nine patients (14 joints) who underwent discectomy of the temporomandibular joint (TMJ). These patients subsequently underwent removal of the implants from 10 to 28 months postplacement due to pain and occlusal changes or radiographic changes in the joints. Light and electron microscopic evaluations were performed on the retrieved implants and surrounding tissue. Evidence of gross deterioration manifested by fracture of the implant was present in 10 of the 14 implants, and microscopic evidence of deterioration was present in all implants. Foreign-body giant cell reaction in surrounding tissues and microfragmentation of the implant were evident in all joints.