• Temporomandibular disorders are caused by problems with the muscles or joints or fibrous tissue connecting them.
• People may have headaches and tenderness of the chewing muscles or may hear clicking of the joints.
• Doctors or dentists can usually diagnose these disorders with a physical examination, but sometimes an imaging test is needed.
• Treatment usually involves splint therapy and pain relief.

The temporomandibular joints are the connections between the temporal bones of the skull and the lower jawbone (mandible). There are two temporomandibular joints, one on each side of the face just in front of the ears. Ligaments,tendons, and muscles support the joints and are responsible for jaw movement.

The temporomandibular joint is one of the most complicated joints in the body: It opens and closes like a hinge and slides forward, backward, and from side to side. During chewing, it may sustain an enormous amount of pressure depending on the position and health of the upper and lower teeth, which act much like a doorstop for the joints during closing. The temporomandibular joint contains a piece of special cartilage called a disk. The disk keeps the skull and the lower jawbone from rubbing against each other.

Temporomandibular disorders, previously called TMJ disorders (temporomandibular joint disorders), are most common among women in their early 20s and between the ages of 40 and 50 (in rare cases, babies are born with temporomandibular joint abnormalities). Temporomandibular disorders include problems with the joints, the muscles, and the bands of fibrous tissue that connect them (fascia).

Most often, the cause of a temporomandibular disorder is a combination of muscle tension and anatomic problems within the joints. Sometimes, there is a psychologic component as well. Specific causes include muscle pain and tightness, internal joint derangement, arthritis, ankylosis, and hypermobility.

Muscle Pain and Tightness: Muscle pain and tightness around the jaw (myofascial pain syndrome) come mainly from muscle overuse, often brought on by problems of misalignment of the upper and lower sets of teeth, missing teeth, injury to the head or neck, or even toothache. Pain is also caused by trying to open the jaw too widely. Muscle pain and tightness can also result from clenching or grinding the teeth (bruxism) at night due to psychologic or sleep-related stress. Clenching and grinding while asleep exert far more force than clenching and grinding while awake.

Internal Joint Derangement: In the most common form of internal joint derangement, the disk inside the joint lies in front of (anterior to) its normal position. Internal joint derangement can occur with or without reduction. Reduction means the parts of a joint have returned to their normal positions. Disk displacement with reduction is more common than displacement without reduction and occurs in about one third of the adult population. In derangement with reduction, the disk lies in front of its normal position only when the mouth is closed. As the mouth opens and the jaw slides forward, the disk slips back into its normal position. As the mouth closes, the disk slips forward again. In internal joint derangement without reduction, the disk never slips back into its normal position, and the degree to which the mouth can be opened is limited.

Ankylosis: Ankylosis is loss of joint movement resulting from fusion of bones within the joint or calcification (the deposit of calcium into body tissues) of the ligaments around it.

Hypermobility: Hypermobility (looseness of the jaw) results when the ligaments that hold the joint together become stretched. In hypermobility, dislocation is usually caused by the shape of the joints, ligament looseness (laxity), and muscle tension. It may be caused by trying to open the mouth too wide or by being struck on the jaw.

Symptoms of temporomandibular disorders include headaches, tenderness of the chewing muscles, and clicking or locking of the joints. Sometimes the pain seems to occur near the joint rather than in it. Temporomandibular disorders may be the reason for recurring headaches that do not respond to usual medical treatment. Other symptoms include pain or stiffness in the neck radiating to the arms, dizziness, earaches or stuffiness in the ears.