Temporomandibular Disorders (TMD)

by Rosalyn Carson-DeWitt, MD

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.

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

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.

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/ . 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.

 

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Last reviewed December 2009 by Robert E. Leach, MD
Last Updated: 12/7/2009