TEMPOROMANDIBULAR JOINT DISORDERS


DEFINITION

Temporomandibular joint disorder (TMJ) is a group of symptoms that involve pain in the head, face, and jaw. Symptoms of TMJ include headaches, soreness in the chewing muscles, and clicking or stiffness of the joints. The disorder can be caused by psychological as well as physical factors. TMJ is also known as temporomandibular joint syndrome.

DESCRIPTION

The temporomandibular joint (pronounced TEM-pu-roh-man-DIBB-yuh-lur) connects the jawbone (the mandible) with the lower part of the skull (the temporal bone). The joint is located in front of the ear. It allows the jaw to move up and down, back and forth, and forward and backward. Various factors can alter the shape or motion of the temporomandibular joint, which may then put pressure on facial nerves. This pressure can result in pain in various parts of the head. Most cases of TMJ occur in women between the age of twenty and fifty.

Temporomandibular Joint Disorders: Words to Know

Arthrography:
An imaging technique in which a dye is injected into a joint to make X-ray pictures of the inside of the joint easier to study.
Internal derangement:
A condition in which the regular arrangement of parts in a system is disturbed. Some cases of TMJ are caused by a particular internal derangement in which the disc in the temporomandibular joint slips out of its normal position.
Mandible:
The scientific term for the lower jaw.
Temporal bones:
The bones that form the right and left sides of the skull.

CAUSES

TMJ syndrome has several possible physical causes:

  • Muscle tension. Overuse of jaw muscles can cause tightness in the temporomandibular joint. A common cause of muscle tightness is stress. People who are overly worried may clench or grind their teeth excessively, which can cause muscle tension.
  • Injury. A direct blow to the jaw or the side of the head can cause TMJ. The blow can break a bone, bruise soft tissue, or dislocate the temporomandibular joint itself.
  • Arthritis (see arthritis entry). Arthritis is a disease of joints caused by a number of factors. Arthritis in the region of the temporomandibular joint can cause TMJ.
  • Internal derangement. The temporomandibular joint contains a small piece of cartilage called a disc, which keeps the jawbone and the temporal bone from rubbing against each other. Sometimes the disc slips out of place creating what is known as an internal derangement. Often this condition can be detected by a clicking or popping sound caused by the disc moving in and out of its correct position. On rare occasions, the disc can become permanently displaced, and a patient may lose the ability to move his or her jaw in all normal ways.
  • Hypermobility. Hypermobility is a condition in which ligaments in the temporomandibular joint become loose. Ligaments are pieces of tissue that hold bones together. In cases of hypermobility, the jaw may slip entirely out of its socket.
  • Birth abnormalities. Children are sometimes born with defects in the temporomandibular joint. For example, the top of the jawbone may be too small. Such causes of TMJ are relatively rare.

SYMPTOMS

The symptoms of TMJ depend in part on its cause. The most common symptoms include the following:

  • Facial pain in front of the ears
  • Headaches
  • Sore jaw muscles
  • A clicking sound when chewing
  • A grinding feeling when opening and closing the mouth
  • Temporary locking of the jaw

Some patients also report a buzzing or ringing in the ears. In most cases, the temporomandibular joint itself is not painful.

DIAGNOSIS

TMJ is most commonly diagnosed by a dentist. The dentist can often tell simply by touching a patient's face if the temporomandibular joint is out of place. Manipulation of the jaw provides additional information. It may be possible to see that the patient's teeth do not close together properly. Looseness in the jaw may indicate hypermobility as well.

Imaging Studies

Imaging studies are used to obtain pictures of the interior of a person's body. X rays are probably the best-known form of imaging studies. In most cases, imaging studies are not very helpful in diagnosing TMJ because the temporomandibular joint will look normal in such studies. Arthrography (pronounced arr-THRAHG-ruh-fee) is one form of imaging that can be useful, however. In arthrography, a dye is injected into the patient's temporomandibular joint. The joint is then observed while being X-rayed. Any abnormal movement of the jaw can be observed by this method.

TREATMENT

The pain associated with TMJ usually goes away on its own without treatment. About 80 percent of patients with the disorder improve in six months without treatment.

Medications

The minor discomfort of TMJ can be treated with pain relievers such as aspirin or acetaminophen. Muscle relaxants may help if the condition is caused by muscle tension. Instances when TMJ is caused by arthritis can be treated with corticosteroids, methotrexate, gold sodium, or other anti-arthritic medications.

Physical Therapy and Mechanical Devices

Some patients experience serious problems with clenching and grinding of their teeth at night. For these patients a plastic splint called a nightguard can be prescribed. The nightguard is placed over the teeth before going to bed. Splints can also be used to hold the jaw and disc in place when these factors are responsible for the disorder.

TMJ can also be treated by a variety of other techniques, such as ultrasound, biofeedback, stretching exercises, electrical nerve stimulation, stress management techniques, or massage.

Surgery

Surgery can be used to place the temporomandibular joint back into its correct position. This approach is used almost exclusively in cases of TMJ caused by birth deformities or internal derangement.

PROGNOSIS

The prognosis for recovery from TMJ is excellent for almost all patients. Most patients do not need any form of long-term treatment. Surgical procedures used to treat TMJ are usually quite successful. The prognosis for cases of TMJ caused by arthritis depends on the progress of the arthritis itself.

PREVENTION

There is no way to prevent TMJ that is caused by physical factors. Stress-induced TMJ can be prevented by learning stress management techniques before the problem starts.

FOR MORE INFORMATION

Books

Shankland, Wesley E. TMJ: Its Many Faces, 2nd edition. Columbus, OH: Anadem, Inc., 1998.

Taddey, John J. TMJ: The Self Help Program. La Jolla, CA: Surrey Park Press, 1990.

Uppgaard, Robert O. Taking Control of TMJ: Your Total Wellness Program for Recovering from Tempromandibular Joint Pain, Whiplash, Fibromyalgia, and Related Disorders. Oakland, CA: New Harbinger Publications, 1999.