The Basics of the Jaw Joint

What Are Temporomandibular Disorders?

Temporomandibular Disorders (TMJD), commonly called TMJ, are a complex and poorly understood set of conditions characterized by pain in the jaw joint and surrounding tissues and limitation in jaw movements. Injury and other conditions that routinely affect other joints in the body, such as arthritis, also affect the temporomandibular joint.  One or both joints may be involved and depending on the severity, can affect a person's ability to speak, eat, chew, swallow, make facial expressions, and even breathe.

Also included under the heading of TMJD are conditions involving the jaw muscles. These may accompany the jaw joint problems or occur independently. They are often confused with jaw joint problems because they produce similar signs and symptoms.

Comorbid (Overlapping) Conditions

Researchers have found that temporomandibular disorders often occur along with other - often painful- conditions in other parts of the body, prompting studies in search of a common factor underlying them all. Among these conditions are chronic fatigue syndrome, chronic headache, endometriosis, fibromyalgia, interstitial cystitis, irritable bowel syndrome, sleep disorders, and vulvodynia. Moreover, certain medical conditions such as Ehlers-Danlose syndrome, dystonia, Lyme disease, and scleroderma may affect the temporomandibular joint. 

Who is Affected?

Approximately 35 million people in the United States suffer from TMJ problems at any given time. While both men and women experience these disorders, the majority of those seeking treatment are women in their childbearing years. The ratio of women to men increases with the severity of symptoms, approaching 9 to 1 for patient with major limitations in jaw movements and chronic, unrelenting pain.

Causes

Although the cause of most of these disorders is not known, there are some known contributing factors to the development of these disorders.

Among them are:

• autoimmune diseases
• infections
• injuries to the jaw area
• dental procedures
• stretching of the jaw as occurs with inserting a breathing tube before surgery
• various forms of arthritis

Genetic, hormonal, and environmental factors can also increase the risk for TMJD. Studies have shown that a particular gene variant increases sensitivity to pain and this variant has been found to be more prevalent among TMJD patients than among the populations at large. The observation that TMJD are commonly found in women in their childbearing years has also led to research to determine the role of female sex hormones in these disorders. Environmental factors such as habitual gum chewing or sustained jaw positions may also contribute to TMJD.

Diagnosis of TMJ Disorders

At present, there is no widely accepted, standard diagnostic test to identify all TMJD. Because the exact cause and symptoms are not clear, identifying these disorders can be difficult and confusing.  The American Association for Dental Research recommends that a diagnosis of TMJD or related orofacial pain conditions should be based primarily on information obtained from the patient's history and a clinical examination of the head and neck.

In addition to a detailed history and a careful clinical examination, imaging studies of the teeth and jaws may sometimes be helpful as a diagnostic tool. These include: routine dental x-rays and panoramic radiographs, computed tomography (CT or CAT scan), Magnetic Resonance Imaging (MRI), and Scintigraphy  (Bone scan).

Blood tests are sometimes recommended to rule out possible medical conditions as a cause of the problem.

Before undergoing any costly diagnostic test, it is always wise to get an independent opinion from another health care provider of your choice and one not associated with your current provider.

Symptoms of TMJ Disorders

The Pain of TMJD is often described as a dull, aching pain which comes and goes in the jaw joint and nearby areas.  Some people, however, report no pain, but still have problems using their jaws.

Symptoms can include:

• pain in the jaw muscles
• pain in the neck and shoulders
• chronic headaches
• jaw muscle stiffness
• limited movement or locking of the jaw
• ear pain, pressure
• painful clicking, popping or grating in the jaw joint when opening or closing the mouth
• a bite that feels "off"

Less common symptoms include: ringing in the ears (tinnitus), dizziness, and vision problems.

NOTE: Jaw noises unaccompanied by pain or decreased mobility do not mean you have a TMJD problem.

Keep in mind that occasional discomfort in the jaw joint or chewing muscles is common, and is not always a cause for concern.  Many people with TMJD get better without treatment. Often the problem goes away on its own in several weeks to months. However, if the pain is severe and lasts more than a few weeks, see your health care provider.

Whom Should You See?

If you think you have a TMJD, you may want to see a medical doctor to rule out some of the conditions that may mimic a TMJD. For example, facial pain can be a symptom of many conditions, such as sinus or ear infections, decayed or abscessed teeth, various types of headache, facial neuralgia (nerve-related facial pain), and even tumors. If the medical doctor or your dentist gives you a diagnosis of a TMJD, it is recommended that you consult our website for guidance regarding treatment.

There is no medical or dental specialty of qualified experts trained in the care and
treatment of TM patients. As a result, there are no established standards of care in clinical practice. Although a variety of health care providers advertise themselves as “TMJ specialists,” the more than 50 different treatments available today are based largely on beliefs, not on scientific evidence.   Sir William Osler, the father of modern medicine, said "that when there are many treatments for a single condition, it is because none of them work."

Because there is no certified specialty in treating TM disorders in either dentistry or medicine, finding the right care can be difficult. The National Institutes of Health advises patients to look for a health care provider who understands musculoskeletal disorders (affecting muscle, bone and joints) and who is trained in treating pain conditions. Pain clinics in hospitals and universities are often a good source of advice, particularly when pain becomes chronic and interferes with daily life.

Complex cases, often marked by chronic and severe pain, jaw dysfunction, comorbid conditions, and diminished quality of life, will likely require a team of doctors from fields such as neurology, rheumatology, pain management and others to diagnose and treat this condition.

Treatment of TMJ Disorders

Most people with TM disorders have relatively mild or periodic symptoms which may improve on their own within weeks or months with simple home therapy. Self-care practices, such as eating soft foods, applying ice or moist heat, and avoiding extreme jaw movements (such as wide yawning, loud singing, and gum-chewing) are useful in easing symptoms.

Scientists strongly recommend treating TMJD with the most conservative approaches possible. These are treatments that do not cause permanent changes in, or change the structure or position of, the jaws or teeth. Even when these disorders have become persistent, most patients still do not need aggressive types of treatment.

If your problems get worse with time, you should seek professional advice. However, first and foremost, educate yourself. Informed patients are better able to communicate with health care providers, ask questions, and make knowledgeable decisions. For information and guidance regarding treatment, read through our treatment section.

Disease Prevention?

Patients who are told they should undergo treatment(s) to prevent the development of a TMJD problem should know that there is currently no evidence that such conditions can be prevented.

Insurance Coverage

Many medical and dental insurance plans do not pay for treatment of TMJD or only pay for some procedures. Until the causes of these disorders have been discovered, and we have scientifically validated safe and effective treatments, insurance companies will not pay for treatments that have questionable outcomes. Contact your insurance company to see which treatments are covered.

Costs

 There are no standardized costs for TMJD treatments.

Complex Conditions

The science on TM disorders is in its infancy and has yet to answer fundamental questions on the causes and risk factors or develop safe and effective treatments and cures.

As research advances to understand more about the TM joint and its associated tissues, many in the health care community are reassessing past treatments and ways in which they were developed. A growing consensus considers TM disorders a complex family of conditions like hypertension or diabetes. In that regard, the TM disorders patient should be seen as a whole individual, subject to a host of genetic, hormonal, environmental and behavioral factors that contribute to his or her state of health or disease. With that perspective, TM disorders cease to be isolated conditions limited to the teeth and jaws, but rather conditions that may coexist with a range of other systemic pain conditions.

There is increasing evidence from research, as well as information compiled by patient health advocacy organizations, that patients with a given chronic condition often experience one or more additional chronic (and often painful) conditions. Among conditions found to overlap with TM disorders are chronic fatigue syndrome, chronic headache, endometriosis, fibromyalgia, interstitial cystitis, irritable bowel syndrome, sleep disorders, and vulvodynia, all disorders that are poorly understood. In some cases, a patient may experience one condition initially and then go on to develop another or others. In other cases, two conditions may occur together at the outset. Such a perspective can direct and inspire scientists to discover commonalities that can advance understanding and ultimately lead to beneficial therapies. Research to understand why these conditions coexist has only recently begun.