Temporomandibular Disorders (TMD)
You may have read articles in newspapers and magazines about "TMD" - temporomandibular (jaw) disorders, also called "TMJ syndrome." Perhaps you have even felt pain at times in your jaw joint area, or maybe your dentist or physician has told you that you have TMD or TMJ problems.
If you have questions about TMD, you are not alone. Researchers, too, are looking for answers to what causes TMD, what are the best treatments, and how we can prevent these disorders.
TMD is not just one disorder, but a group of conditions, often painful or debilitating, that affect the jaw joint (temporomandibular joint or TMJ) or the muscles, tendons, and ligaments that control chewing. Although we don't know how many people actually have TMD, the disorders appear to affect about twice as many women as men.
The good news is that for most people, pain in the area of the jaw joint or muscles is not a signal that a serious problem is developing. Generally, discomfort from TMD is occasional and temporary, often occurring in cycles. The pain eventually goes away with little or no treatment. Only a small percentage of people with TMD pain develop significant, long-term symptoms.
What is the Temporomandibular Joint?
The temporomandibular joint connects the lower jaw, called the mandible, to the temporal bone at the side of the head. if you place your fingers just in front of your ears and open your mouth, you can feel the joint on each side of your head. because these joints are flexible, the jaw can move smoothly up and down or side to side, enabling us to talk, chew, and yawn. Muscles, ligaments and tendons attached to and surrounding the jaw joint control jaw position and movement.
When we open our mouths, the rounded ends of the lower jaw, called condyles, glide along the joint socket of the temporal bone. The condyles slide back to their original position when we close our mouths. To keep this motion smooth, a soft disc lies between the condyle and the temporal bone. This disc absorbs shocks to the TMJ from chewing and other movements.
What Are Temporomandibular Disorders?
Today, researchers generally agree that temporomandibular disorders fall into several major groups:
A person may have one or more of these conditions at the same time.
What Causes TMD?
We know that severe injury to the jaw or temporomandibular joint can cause TMD. A heavy blow, for example, can fracture the bones of the joint or damage the disc, disrupting the smooth motion of the jaw and causing pain or locking. Arthritis in the jaw joint may also result from injury.
Other causes of TMD are less clear. Some suggest, for example, that a bad bite (malocclusion) can trigger TMD, but recent research disputes that view. Orthodontic treatment, such as braces and the use of headgear, has also been blamed for some forms of TMD, but studies now show that this is unlikely.
And there is no scientific proof that gum chewing causes clicking sounds in the jaw joint, or that jaw clicking leads to serious TMJ problems. In fact, jaw clicking is fairly common in the general population. If there are no other symptoms, such as pain or locking, jaw clicking usually does not need treatment.
Researchers believe that most people with clicking or popping in the jaw joint likely have a displaced disc -- the soft, shock-absorbing disc is not in a normal position. As long as the displaced disc causes no pain or problems with jaw movement, no treatment is needed.
Some experts suggest that stress, either mental or physical, may cause or aggravate TMD. People with TMD often clench or grind their teeth at night, which can tire the jaw muscles and lead to pain. It is not clear, however, whether stress is the cause of the clenching/grinding and subsequent jaw pain, or the result of dealing with chronic jaw pain or dysfunction. Scientists are exploring how behavioral, psychological and physical factors may combine to cause TMD.
TMD Signs and Symptoms
A variety of symptoms may be linked to TMD. Pain, particularly in the chewing muscles and/or jaw joint, is the most common symptom. Other likely symptoms include:
Symptoms such as headaches, earaches, dizziness and hearing problems may sometimes be related to TMD. It is important to keep in mind, however, that occasional discomfort in the jaw joint or chewing muscles is quite common and is generally not a cause for concern. Researchers are working to clarify TMD symptoms, with the goal of developing easier and better methods of diagnosis and improved treatment.
Because the exact causes and symptoms of TMD are not clear, diagnosing these disorders can be confusing. Without a clear diagnosis, treatment can be a hit or miss affair at considerable expense. Dr. Fox has been caring for patients with TMD and craniofacial pain for many years, and has unusual expertise in this dental subspecialty area. He sees patients referred by their dentists for help with TMD problems, and also welcomes patients to arrange for evaluation without a doctor's referral. In about 90 percent of cases, he can restore comfort and function in a short period of time at reasonable expense.
The foundation for an accurate diagnosis is a detailed history of the patient's problems coupled with a thorough examination. The examination includes feeling the jaw joints and chewing muscles for pain or tenderness; listening for clicking, popping or grating sounds during jaw movement; and examining for limited motion or locking of the jaw while opening or closing the mouth. Checking the patient's dental and medical history is very important. In most cases, this evaluation provides enough information to locate the pain or jaw problem, to make a diagnosis, and to start treatment to relieve pain or jaw locking.
Regular dental X-rays and TMJ x-rays (transcranial radiographs) are often helpful in diagnosing TMD. Other x-ray techniques, such as arthrography (joint x-rays using dye); magnetic resonance imaging (MRI), which pictures the soft tissues; and tomography (a special type of x-ray) may be needed in some cases. But these imaging methods are usually needed only when a condition such as arthritis is suspected, or when significant pain persists over time and symptoms do not improve with treatment.
The key words to keep in mind about TMD treatment are "conservative" and "reversible." Conservative treatments are as simple as possible and are used most often because most patients do not have severe, degenerative TMD. Conservative treatments do not invade the tissues of the face, jaw or joint. Reversible treatments do not cause permanent, or irreversible, changes in the structure or position of the jaw or teeth.
Because most TMD problems are temporary and do not get worse, simple treatment is all that is usually needed to relieve discomfort. Self-care practices, for example, eating soft foods, applying heat or ice packs, and avoiding extreme jaw movements (such as wide yawning, loud singing and gum chewing) are useful in easing TMD symptoms. Learning special techniques for relaxing and reducing stress may also help patients deal with pain that often comes with TMD problems.
Other conservative, reversible treatments include physical therapy you can do at home, which focuses on gentle muscle stretching and relaxing exercises, and short-term use of muscle-relaxing and anti-inflammatory drugs.
The health care provider may recommend an orthotic oral appliance, also called a splint or bite plate, which is a plastic guard that fits over the upper teeth. The splint can help reduce clenching or grinding, which eases muscle tension. If you are using an oral appliance that causes or increases pain, stop using it and see your practitioner.
The conservative, reversible treatments described are useful for temporary relief of pain and muscle spasm -- they are not "cures" for TMD. If symptoms continue over time or come back often, check with your doctor.
There are other types of TMD treatment, such as surgery or injections, that invade the tissues. Some involve injecting pain relieving medications or anti-inflammatory into painful muscle sites, often called "trigger points."
Surgical treatments are often irreversible and should be avoided where possible. When such treatment is necessary, be sure to have the doctor explain to you, in words you can understand, the reason for the treatment, the risks involved, and other types of treatment that may be available. Scientists have learned that certain irreversible treatments, such as surgical replacement of jaw joints with artificial implants, may cause severe pain and permanent jaw damage. Some of these devices may fail to function properly or may break apart in the jaw over time. Before undergoing any surgery on the jaw joint, it is very important to get other independent opinions.
Although more studies are needed on the safety and effectiveness of most TMD treatments, scientists strongly recommend using the most conservative, reversible treatments possible before considering invasive treatments. Even when the TMD problem has become chronic, most patients still do not need aggressive types of treatment.
If You Think You Have TMD...
Keep in mind that for some people, discomfort from TMD will eventually go away whether treated or not. Simple self-care practices are often effective in easing TMD symptoms. If more treatment is needed, it should be conservative and reversible. Treatments that cause permanent changes in the bite or jaw should be undertaken only by highly trained dentists, and then only in exceptional cases.
Many practitioners, especially dentists, are familiar with the conservative treatment of TMD. Dr. Fox has advanced training, experience and expertise in this highly specialized area of dental care.