The temporomandibular joint (TMJ) surfaces are formed by the skull and the the jaw. The surfaces are covered by cartilage.

Certain conditions may indicate the need for a replacement for the TMJ joint such as: osteoarthritis (shown), fractures, fused joints, abnormalities that reduce function, and tumors.

A replacement joint can help alleviate pain and improve function. The replacement joint usually has two parts that replace the joint surfaces and is made of a combination of metal and plastic.

Figure 1: Comparison of a normal TMJ joint and a replacement TMJ joint.
Figure 2: Normal TMJ joint.
Figure 3: A damaged TMJ joint.
Figure 4: Replacement TMJ joint