Temporomandibular Joint Disor... Health Article

Definition

Temporomandibular joint (TMJ) disorder, also known as TMD, is the name given to a group of symptoms that cause pain in the facial muscles and dysfunction in the head, face, and jaw. TMD often has psychological as well as physical causes.

Description

TMD results from pressure on the facial nerves due to muscle tension, injury, or bone abnormalities. Some 70% of adults exhibit at least one sign of TMD, but only 5% seek treatment. Most sufferers are women between ages 20 and 50.

The TMJ connects the temporal bone with the condyle of the mandible anterior to the ear on each side of the skull. The jaw pivots on ligaments, tendons, and muscles to allow motion downward and laterally as well as forward. Anything that causes a change in shape or functioning of the TMJ can cause pain and other symptoms.

Causes

TMD has varied causes:

• Bruxism, or unconscious clenching or grinding of the teeth, is the most common cause of TMD. Bruxism occurs during periods of stress or during sleep. It results in muscle tension and soreness around the jaw joint and in the facial muscles.
• Misalignment of the teeth or displacement of the TMJ disc may contribute to TMD.
• Injury to the jaw or side of the head, either from a direct blow or from repeated and prolonged opening and closing (as in gum chewing), can result in a dislocation of the TMJ and subsequent TMD problems.
• Arthritis in different forms can lead to TMD. Traumatic arthritis from an injury, osteoarthritis, and rheumatoid arthritis are all possible causes.
• Hypermobility, a condition in which the ligaments of the TMJ are too loose, may allow the mandible to slip out of position and create TMD.
• Poor posture is another potential cause of TMD. When an individual carries his or her head too far forward and strains the neck muscles, TMD can result. In one research study in Texas, patients who were given posture training along with traditional treatment had greater improvement than those without posture training.
• Birth abnormalities are the least frequent cause of TMD, but can occur. In some cases, the condyle of the mandible is too large or too small.

KEY TERMS

Arthrography—A testing technique in which a special dye is injected into the joint, which is then x rayed.

Bruxism—Habitual clenching and grinding of the teeth, especially during sleep.

Condyle—An articular prominence of a bone.

Electromyographic biofeedback—A method for relieving jaw tightness by monitoring the patient's attempts to relax the muscle while the patient watches a gauge. The patient gradually learns to control the degree of muscle relaxation.

Fibromyalgia—A complex, chronic condition which causes widespread pain and fatigue, as well as a variety of other symptoms.

Malocclusion—The misalignment of opposing teeth in the upper and lower jaws.

Mandible—The lower jaw.

Orofacial—Pertaining to the mouth and face.

Osteoarthritis—A type of arthritis marked by chronic degeneration of the cartilage of the joints, leading to pain and sometimes loss of function.

Rheumatoid arthritis—A chronic autoimmune disorder marked by inflammation and deformity of the affected joints.

Temporal bones—The compound bones that form the right and left sides of the skull above the ears.

Tinnitus—A sensation of ringing or roaring in the ears that can only be heard by the individual affected.

Transcutaneous electrical nerve stimulation—A method for relieving the muscle pain of TMD by stimulating nerve endings that do not transmit pain. It is thought that this stimulation blocks impulses from nerve endings that do transmit pain.

Symptoms

The symptoms of TMD depend in part on its cause. They include orofacial pain, restricted jaw function, and clicking or stiffness in the joints. Patients may also suffer from headaches, ear, neck, and shoulder pain, or tinnitus. Classic symptoms are pain in front of the ear that spreads to the ear, mandible, cheek, and temple. Pain may be worse in the morning, and may be cyclical. Patients may also report noise in the joint during chewing, and limited mouth opening.

Physical examination and patient history

TMD is most frequently diagnosed in the dental office based on physical examination. As the patient opens, closes, and moves the jaw laterally, palpation (physical examination by feeling with the hands) can detect joint popping and clicking, or a stethoscope may be placed in front of the ear to listen to the jaw movements. Jaw and facial muscles are checked for tenderness, and the patient's bite is checked for misalignment.

A careful patient history looks for such clues as recent injury or recent dental work. The patient should be asked about the duration and severity of jaw and face pain. Any history of insomnia, stress, anxiety, depression, chronic pain, or fibromyalgia should be documented.