Whiplash may produce delayed jaw pain( CHICAGO Aug. 16 2007 One in three p...),Health

CHICAGO, Aug. 16, 2007 One in three people exposed to whiplash trauma is at risk of developing delayed TMJ symptoms that may require treatment, according to research published in the August issue of The Journal of the American Dental Association.

Researchers at Ume University, Sweden, studied short- and long-term temporomandibular joint (TMJ) pain and dysfunction in 60 patients in hospital emergency rooms directly after they were involved in a rear-end car collision and evaluated them again one year later.

According to the study, the incidence of new symptoms of TMJ pain, dysfunction or both between the initial examination and follow-up was five times higher in subjects than in uninjured control subjects. In the year between the two examinations, 7 percent of control subjects developed symptoms in the TMJ versus 34 percent of study subjects.

According to the American Dental Association, the TM joint is one of the most complex joints in the body. Located on each side of the head, these joints work together and can make many different movements, including a combination of rotating and translocational (gliding) action, used when chewing and speaking. Any problem that prevents this system of muscles, ligaments, discs and bones from working together properly may result in a painful TMJ disorder.

When the patients reported having symptoms in the TMJ either before or after their accidents or both, the authors evaluated symptoms, including clicking, locking and TMJ pain. They also asked patients to rate their pain intensity and report the degree to which symptoms interfered with their daily lives, including sleep disturbances, use of pain relievers and the need to take sick leave.

One in three people who are exposed to whiplash trauma, which induces neck symptoms, is at risk of developing delayed TMJ pain and dysfunction during the year after the accident, the researchers concluded.