Aug. 31 (HealthDay News) -- About one in three people who suffer whiplash is at risk of developing delayed jaw pain/dysfunction that may require treatment, a Swedish study finds.

Publishing in the August issue of the Journal of the American Dental Association, researchers at Umea University studied short- and long-term temporomandibular joint (TMJ) pain and dysfunction in 60 patients involved in rear-end car collisions. The patients were checked when they were brought to hospital emergency rooms after a crash, and again one year later.

Patients who suffered whiplash were five times more likely to have TMJ pain and/or dysfunction immediately after a crash than uninjured people in a control group. A year later, 34 percent of whiplash patients had developed TMJ symptoms, compared with 7 percent of those in the control group.

The TM joints, located on each side of the head, work together to enable movements needed to speak and chew. Problems that affect the proper function of this system of muscles, ligaments, discs and bones can result in a painful TMJ disorder, according to the American Dental Association.

SOURCE: American Dental Association, news release, August 2007