GARY NEILL

By JANE E. BRODY


One person gets migraine headaches, another ringing in the ears, a third clicking and locking of the jaw, a fourth pain on the sides and back of the head and neck. All are suspected of having a temporomandibular disorder.

Up to three-fourths of Americans have one or more signs of a temporomandibular problem, most of which come and go and finally disappear on their own. Specialists from Boston estimate that only 5 percent to 10 percent of people with symptoms need treatment.

Popularly called TMJ, for the joint where the upper and lower jaws meet, temporomandibular disorders actually represent a wider class of head pain problems that can involve this sensitive joint, the muscles involved in chewing, and related head and neck muscles and bones.

But too often, experts say, patients fail to have the problem examined in a comprehensive way and undergo costly and sometimes irreversible therapies that may do little or nothing to relieve their symptoms. As scientists at the National Institute of Dental and Craniofacial Research wrote recently,“Less is often best in treating TMJ disorders.”

The TMJ is a complicated joint that connects the lower jaw to the temporal bone at the side of the head. It has both a hinge and a sliding motion. When the mouth is opening, the rounded ends, or condyles, of the lower jaw glide along the sockets of the temporal bones. Muscles are connected to both the jaw and the temporal bones, and a soft disc between them absorbs shocks to the jaw from chewing and other jaw movements.

As the researchers from Boston wrote recently in The New England Journal of Medicine,“the cause is now considered multifactorial, with biologic, behavioral, environmental, social, emotional and cognitive factors, alone or in combination, contributing to the development of signs and symptoms of temporomandibular disorders.”

Among the“mechanical”causes that are now recognized as distorting the function of the TMJ are congenital or developmental abnormalities of the jaw; displacement of the disc between the jaw bones; inflammation or arthritis; traumatic injury to the joint; infection; and excessive laxity or tightness of the joint.

But the most common TMJ problem is known as myofacial pain disorder, a neuromuscular problem of the chewing muscles characterized by a dull, aching pain in and around the ear that may radiate to the side or back of the head or down the neck. Someone with this disorder may have tender jaw muscles, hear clicking or popping noises in the jaw, or have difficulty opening or closing the mouth.

The overwhelming majority of people with TMJ symptoms are women. Women represent up to 90 percent of patients who seek treatment, Dr.Leonard B.Kaban, chief of oral and maxillofacial surgery at the Massachusetts General Hospital in Boston, said.

Resting the jaw is the most important therapy. Stop harmful chewing and biting habits and avoid opening the mouth wide while yawning or laughing. It also helps to apply heat to the side of the face and to take a nonsteroidal anti-inflammatory medication, for up to two weeks.

Physical therapy to retrain positioning of the spine, head, jaw and tongue can be helpful. But Dr.Kaban cautioned against embarking on“any expensive, irreversible treatment”before a thorough diagnosis is completed and simple, reversible therapies have been tried and found wanting.