Definition

Temporomandibular joint syndrome, also known as temporomandibular joint disorder or TMD, is a painful condition involving the joint that opens and closes the mouth. The temporomandibular joints are the small joints in front of each ear that attach the lower jaw (mandible) to the skull. The disorder may affect the jaw joint or the muscles surrounding it.

	The Temporomandibular Joint
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Causes

The exact cause of TMD syndrome is often unclear. Possible causes include:

• Excess tension in the jaw muscles
• Faulty alignment between the upper and lower teeth and jaws
• Disturbed movement of the jaw joint
• Displacement or abnormal position of the jaw joint or cartilage disc inside the jaw joint
• Arthritis or similar inflammatory process in the joint
• Excess or limited motion of the joint
• Injury of the jaw or face

Risk Factors

A risk factor is something that increases your chance of getting a disease or condition.

Risk factors include:

• Sex: female
• Age: 30 to 50 years old
• Clenching or grinding of teeth
• Poorly fitting dentures or crowns
• Fibromyalgia
• Stress
• Arthritis

Symptoms

Symptoms include:

• Pain in the temporomandibular joint, jaw, or face
• Pain may be worse with chewing, yawning, or opening the mouth
• Clicking, popping, or grating sounds with movement of the jaw
• A sensation of the jaw “catching” or “locking” briefly, while attempting to open or close the mouth, or while chewing
• Difficulty opening the mouth completely
• A bite that feels "off," uncomfortable, or as though it is frequently changing
• Swelling in the affected side of the face or mouth
• Painful muscle spasm in the area of the temporomandibular joint
• Headache
• Earache
• Neck, back, and/or shoulder pain

Diagnosis

The doctor will ask about your symptoms and medical history, and perform a physical exam. The physical exam may include:

• Range of motion tests
• Listening for sounds of popping or clicking in the temporomandibular joints
• Visual inspection of your teeth, temporomandibular joints, and muscles of your face and head
• Palpation of the joints and the muscles of the face and head

Other tests may include:

• X-rays—plain x-rays or panoramic dental x-rays of the jaw and jaw joint; they show the teeth.
• Arthrography—jaw movements videotaped with x-rays taken after dye is injected into the joint
• MRI scan—a test that uses magnetic waves to create detailed images of the joint

Treatment

Treatment may include:

Lifestyle Measures

Resting the jaw with a soft diet, restricting its movement through smaller bites, and applying warm packs may offer considerable relief. Cognitive behavior therapy can help some patients learn to avoid clenching and grinding their teeth.

Medications

The most commonly used medicines include:

• Acetaminophen
• Nonsteroidal anti-inflammatory drugs
• Muscle relaxants
• Low-dose antidepressants

In some cases, the jaw joint may be injected with pain relieving medicine such as cortisone or lidocaine. When pain or clicking are major symptoms, injections of botulinum toxin (Botox) may offer temporary relief that responds to retreatment.

Physical Therapy

Gentle massage or stretching exercises, and transcutaneous electrical nerve stimulation (TENS) may reduce pain and help muscles relax in some patients.

Stress Reduction

Counseling to learn stress management and relaxation techniques, including biofeedback and cognitive behavioral therapy, * may help some patients with TMD.

Dental Procedures

A splint or mouth guard, usually worn at night, can be made to relax your jaw muscles and prevent clenching and grinding of your teeth. Correction of bite abnormalities by a dentist or orthodontist is sometimes recommended.

Surgical Procedures

Surgical correction is a last resort if other treatments have not succeeded and the pain persists. Many of the available procedures have not been well-studied for their effectiveness.

Prevention

There are no guidelines for preventing TMD. If you have TMD, the following may help prevent symptoms:

• Ask your dentist if you need a night guard for grinding and clenching of the teeth.
• Try to limit jaw movements and learn to relax your jaw. Block a yawn by putting your fist under your chin.
• Avoid extensive movements of the jaw.
• Don't chew gum.
• Learn relaxation techniques and effective ways to cope with stress.

RESOURCES:

American Dental Association
http://www.ada.org

The TMJ Association
http://www.tmj.org

CANADIAN RESOURCES:

Canadian Dental Association
http://www.cda-adc.ca/

Canadian Society of Otolaryngology—Head & Neck Surgery
http://www.entcanada.org

References:

Borodic GE, Acquadro MA. The use of botulinum toxin for the treatment of chronic facial pain. J Pain. 2002 Feb;3(1):21-7.

Haley DP, Schiffman EL, Lindgren BR, Anderson Q, Andreasen K. The relationship between clinical and MRI findings in patients with unilateral temporomandibular joint pain. J Am Dent Assoc. 2001;132(4):476-81.

National Institute of Dental and Craniofacial Research website. Available at: http://www.nidcr.nih.gov/.

*Updated section on Stress Reduction on 6/29/06 according to the following study, as cited by DynaMed's Systematic Literature Surveillance : Turner JA, Mancl L, Aaron LA. Short- and long-term efficacy of brief cognitive-behavioral therapy for patients with chronic temporomandibular disorder pain: a randomized, controlled trial Pain. 2006;121(3):171-2.

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