Temporalis muscle as a disc replacement in the temporomandibular joint of sheep.

Temporalis muscle flaps were evaluated in sheep. Flaps placed following discectomy were examined at 2, 4, 12, and 24 weeks. Histologic evaluation showed avascular necrosis and subsequent displacement and loss of tissue from the joint resulting in close contact between the condyle and fossa. Muscle flaps placed lateral to the joint in operative controls were examined at 4, 12, and 24 weeks. This muscle remained viable while undergoing fibrous replacement. Although the surface layers of the condyle and fossa were initially lost, the tissues were reformed with time. This experiment showed that in the sheep, temporalis muscle does not withstand functional loading within the joint. However, despite the lack of interpositional material, the condyle and fossa can remodel.