Conditions InDepth: Temporomandibular Disorders (TMD)

Temporomandibular disorders (TMD) involves the two joints that attach the lower jaw (mandible) to the skull. These two joints open and close the mouth, and are located directly in front of your ears.

Adult Skull Showing Temporomandibular Joint

Adult Skull Showing TMJ and Muscles

© 2008 Nucleus Medical Art, Inc.

You may have TMD if:

  • The temporomandibular joints (TMJ) are chronically inflamed and sore
  • The muscles that work the temporomandibular joints are regularly in spasm
  • The cushioning disc that should rest between the temporomandibular joint and the skull becomes worn out or displaced

Researchers do not exactly know what causes TMD. Some people have had accidents or injuries involving their jaw, but many others have had no such incident. Some of the possible causes include:

  • Grinding the teeth or clenching the jaw in response to stress (known as bruxism)
  • Arthritis of the temporomandibular joint
  • History of injury or trauma to the joint
  • Facial bone defects
  • Misalignments of the jaw or of the bite

Enlargement of TMJ With Jaw Open

Enlargement of TMJ with Open Jaw

© 2008 Nucleus Medical Art, Inc.

TMD symptoms may originate within the joint itself (least common) or from the muscles that surround the joint. The treatment of these two variants of TMD may differ. Recent research suggests that genetic factors may be associated with TMD symptoms.

Some research suggests that as many as 70% of all adults have at least one sign of TMD during physical or dental exam of the temporomandibular joints. However, only about 25% of all adults describe accompanying symptoms, and only about 5% seek treatment for their symptoms.

What are the risk factors for TMD?
What are the symptoms of TMD?
How is TMD diagnosed?
What are the treatments for TMD?
Are there screening tests for TMD?
How can I reduce my risk of TMD?
What questions should I ask my doctor?
What is it like to live with TMD?
Where can I get more information about TMD?

References:

Cummings CW. Otolaryngology: Head & Neck Surgery. 4th ed. St. Louis, MO: Mosby; 2005.

Dambro MR. Griffith’s 5-Minute Clinical Consult. Philadelphia, PA: Lippincott Williams & Wilkins; 2006.

Diatchenko L, Slade GD, Nackley AG, et al. Genetic basis for individual variations in pain perception and the development of a chronic pain condition. Hum Mol Genet. 2005;14:135-143.

Nackley AG, Tan KS, Fecho K, Flood P, Diatchenko L, Maixner W. Catechol-O-methyltransferase inhibition increases pain sensitivity through activation of both beta(2)- and beta(3)-adrenergic receptors (published electronically ahead of print). Pain. Nov 3, 2006.

Okeson, Jeffrey. Clinical Management of Temporomandibular Disorders and Occlusion. 6th ed. St. Louis, MO: Mosby 2007.

Siccoli MM. Facial pain: a clinical differential diagnosis. Lancet Neurology . 2006;5:257-267.

TMD/TMJ (temporomandibular disorders). American Dental Association website. Available at: http://www.ada.org/public/topics/tmd_tmj.asp. Accessed September 17, 2008.

TMJ. American Academy of Otolaryngology—Head and Neck Surgery website. Available at: http://www.entnet.org/HealthInformation/tmj.cfm. Accessed September 17, 2008.

TMJ (temporomandibular joint and muscle disorders). National Institute of Dental and Craniofacial Research website. Available at: http://www.nidcr.nih.gov/OralHealth/Topics/TMJ/. Updated August 2008. Accessed September 17, 2008.



Last reviewed June 2008 by Laura Morris-Olson, DMD

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.


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