Temporomandibular [tem-puh-roh-man-dib-yuh-ler] joint
– The mandible, the lower jaw bone, is the only movable facial bone. the mandible unites with the temporal bone at the temporomandibular joint.
TMJD/TMD – Temporomandibular Joint Disorder
– Temporomandibular joint and muscle disorders (TMJ disorders) are problems that affect the chewing muscles and joints that connect your lower jaw to your skull.
What are TMJ disorders?
Disorders of the jaw joint and chewing muscles—and how people respond to them—vary widely. Researchers generally agree that the conditions fall into three main categories:
- Myofascial pain involves discomfort or pain in the muscles that control jaw function.
Myofascial pain syndrome is a disorder in which pressure on sensitive points in the muscles causes pain in seemingly unrelated body parts. The syndrome often happens after repeated injury or muscle overuse.Symptoms include persistent pain or a tender muscle knot.
- Internal derangement of the joint involves a displaced disc, dislocated jaw, or injury to the condyle.
The most common form of internal temporomandibular joint derangement is anterior misalignment or displacement of the articular disk above the condyle. Symptoms are localized joint pain and popping on jaw movement. Diagnosis is based on history and physical examination. Treatment is with analgesics, jaw rest, muscle relaxation, physical therapy, and bite splinting. If these methods fail, surgery may be necessary. Early treatment greatly improves results.
- Arthritis refers to a group of degenerative/inflammatory joint disorders that can affect the temporomandibular joint.
Jaw pain, difficulty chewing, and clicking and locking of the jaw joint are some of the symptoms.Common treatments include medications, bite guards, and physical therapy.
A person may have one or more of these conditions at the same time. Some people have other health problems that co-exist with TMJ disorders, such as chronic fatigue syndrome, sleep disturbances or fibromyalgia, a painful condition that affects muscles and other soft tissues throughout the body. These disorders share some common symptoms, which suggests that they may share similar underlying mechanisms of disease. However, it is not known whether they have a common cause.
Rheumatic disease, such as arthritis, may also affect the temporomandibular joint as a secondary condition. Rheumatic diseases refer to a large group of disorders that cause pain, inflammation, and stiffness in the joints, muscles, and bone. Arthritis and some TMJ disorders involve inflammation of the tissues that line the joints. The exact relationship between these conditions is not known.
How jaw joint and muscle disorders progress is not clear. Symptoms worsen and ease over time, but what causes these changes is not known. Most people have relatively mild forms of the disorder. Their symptoms improve significantly, or disappear spontaneously, within weeks or months. For others, the condition causes long-term, persistent and debilitating pain.
What are the signs and symptoms?
A variety of symptoms may be linked to TMJ disorders. Pain, particularly in the chewing muscles and/or jaw joint, is the most common symptom. Other likely symptoms include:
- radiating pain or tenderness in the face, jaw, or neck,
- jaw muscle stiffness,
- pain in one or both of the temporomandibular joints,
- aching pain in and around your ear,
- limited movement or locking of the jaw,
- difficulty chewing or pain while chewing,
- painful clicking, popping or grating in the jaw joint when opening or closing the mouth,
- a change in the way the upper and lower teeth fit together.
When to see a doctor
Seek medical attention if you have persistent pain or tenderness in your jaw, or if you can’t open or close your jaw completely. Your doctor, your dentist or a TMJ specialist can discuss possible causes and treatments of your problem.
Remember that for most people, discomfort from TMJ disorders will eventually go away on its own. Simple self-care practices are often effective in easing symptoms. If treatment is needed, it should be based on a reasonable diagnosis, be conservative and reversible, and be customized to your special needs. Avoid treatments that can cause permanent changes in the bite or jaw. If irreversible treatments are recommended, be sure to get a reliable, independent second opinion.
Because there is no certified specialty for TMJ disorders in either dentistry or medicine, finding the right care can be difficult. 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 continues over time and interferes with daily life. Complex cases, often marked by prolonged, persistent and severe pain; jaw dysfunction; co-existing conditions; and diminished quality of life, likely require a team of experts from various fields, such as neurology, rheumatology, pain management and others, to diagnose and treat this condition.
The temporomandibular joint (TMJ) combines a hinge action with sliding motions. The parts of the bones that interact in the joint are covered with cartilage and are separated by a small shock-absorbing disk, which normally keeps the movement smooth.
Trauma to the jaw or temporomandibular joint plays a role in some TMJ disorders. But for most jaw joint and muscle problems, scientists don’t know the causes. Because the condition is more common in women than in men, scientists are exploring a possible link between female hormones and TMJ disorders.
For many people, symptoms seem to start without obvious reason. Research disputes the popular belief that a bad bite or orthodontic braces can trigger TMJ disorders.
There is no scientific proof that sounds—such as clicking—in the jaw joint lead to serious problems. In fact, jaw sounds are common in the general population. Jaw noises alone, without pain or limited jaw movement, do not indicate a TMJ disorder and do not warrant treatment.
Painful TMJ disorders can occur if:
- The disk erodes or moves out of its proper alignment
- The joint’s cartilage is damaged by arthritis
- The joint is damaged by a blow or other impact
Diagnosis of disk derangement with reduction requires observation of the jaw when the mouth is opened. When the jaw is opened > 10 mm (measured between upper and lower incisors), a click or pop is heard, or a catch is felt, as the disk pops back over the head of the condyle. The condyle remains on the disk during further opening. Usually, another, more subtle (reciprocal) click is heard during closing when the condyle slips over the posterior rim of the disk and the disk slips forward.
Diagnosis of disk derangement without reduction requires that the patient open as wide as possible. The opening is measured, and gentle pressure is then exerted to open the mouth a little wider. Normally, the jaw opens about 45 to 50 mm; if the disk is deranged, it will open about ≤ 30 mm. Closing or protruding the jaw against resistance worsens the pain.
MRI is usually done to confirm presence of a disk derangement or to determine why a patient is not responding to treatment.
Capsulitis is often diagnosed based on a history of injury or infection along with exquisite tenderness over the joint and by exclusion when pain remains after treatment for myofascial pain syndrome, disk derangement, arthritis, and structural asymmetries. However, capsulitis may be present with any of these conditions.
Because more studies are needed on the safety and effectiveness of most treatments for jaw joint and muscle disorders, experts strongly recommend using the most conservative, reversible treatments possible. Conservative treatments do not invade the tissues of the face, jaw, or joint, or involve surgery. Reversible treatments do not cause permanent changes in the structure or position of the jaw or teeth. Even when TMJ disorders have become persistent, most patients still do not need aggressive types of treatment.
Because the most common jaw joint and muscle problems are temporary and do not get worse, simple treatment may be all that is necessary to relieve discomfort.
There are steps you can take that may be helpful in easing symptoms, such as:
- eating soft foods,
- applying ice packs,
- avoiding extreme jaw movements (such as wide yawning, loud singing, and gum chewing),
- learning techniques for relaxing and reducing stress,
- practicing gentle jaw stretching and relaxing exercises that may help increase jaw movement. Your health care provider or a physical therapist can recommend exercises if appropriate for your particular condition.
For many people with TMJ disorders, short-term use of over-the-counter pain medicines or nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, may provide temporary relief from jaw discomfort. When necessary, your dentist or physician can prescribe stronger pain or anti-inflammatory medications, muscle relaxants, or anti-depressants to help ease symptoms.
Your physician or dentist may recommend an oral appliance, also called a stabilization splint or bite guard, which is a plastic guard that fits over the upper or lower teeth. Stabilization splints are the most widely used treatments for TMJ disorders. Studies of their effectiveness in providing pain relief, however, have been inconclusive. If a stabilization splint is recommended, it should be used only for a short time and should not cause permanent changes in the bite. If a splint causes or increases pain, or affects your bite, stop using it and see your health care provider.
The conservative, reversible treatments described are useful for temporary relief of pain – they are not cures for TMJ disorders. If symptoms continue over time, come back often, or worsen, tell your doctor.
Botox® (botulinum toxin type A) is a drug made from the same bacterium that causes food poisoning. Used in small doses, Botox injections can actually help alleviate some health problems and have been approved by the Food and Drug Administration (FDA) for certain disorders. However, Botox is currently not approved by the FDA for use in TMJ disorders.
Results from recent clinical studies are inconclusive regarding the effectiveness of Botox for treatment of chronic TMJ disorders. Additional research is under way to learn how Botox specifically affects jaw muscles and their nerves. The findings will help determine if this drug may be useful in treating TMJ disorders.
Irreversible treatments that have not been proven to be effective – and may make the problem worse – include orthodontics to change the bite; crown and bridge work to balance the bite; grinding down teeth to bring the bite into balance, called “occlusal adjustment”; and repositioning splints, also called orthotics, which permanently alter the bite.
Other types of treatments, such as surgical procedures, invade the tissues. Surgical treatments are controversial, often irreversible, and should be avoided where possible. There have been no long-term clinical trials to study the safety and effectiveness of surgical treatments for TMJ disorders. Nor are there standards to identify people who would most likely benefit from surgery. Failure to respond to conservative treatments, for example, does not automatically mean that surgery is necessary. If surgery is recommended, 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.
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. If you have already had temporomandibular joint surgery, be very cautious about considering additional operations. Persons undergoing multiple surgeries on the jaw joint generally have a poor outlook for normal, pain-free joint function. Before undergoing any surgery on the jaw joint, it is extremely important to get other independent opinions and to fully understand the risks.
The U.S. Food and Drug Administration (FDA) monitors the safety and effectiveness of medical devices implanted in the body, including artificial jaw joint implants. Patients and their health care providers can report serious problems with TMJ implants to the FDA through MedWatch at www.fda.gov/medwatch or telephone toll-free at 1-800-332-1088.
Complementary and alternative medicine techniques may help manage the chronic pain often associated with TMJ disorders. Examples include:
- Acupuncture. A specialist trained in acupuncture treats chronic pain by inserting hair-thin needles at specific locations on your body.
- Relaxation techniques. Consciously slowing your breathing and taking deep, regular breaths can help relax tense muscles, which can reduce pain.
- Biofeedback. Electronic devices that monitor the tightness of specific muscles can help you practice effective relaxation techniques.
Factors that increase the risk of developing TMJ disorders include:
- Various types of arthritis, such as rheumatoid arthritis and osteoarthritis
- Jaw injury
- Long-term (chronic) grinding or clenching of teeth
- Certain connective tissue diseases that cause problems which may affect the temporomandibular joint
The National Institute of Dental and Craniofacial Research (NIDCR), one of the National Institutes of Health (NIH), leads the federal research effort on temporomandibular joint and muscle disorders. In a landmark study, NIDCR is tracking healthy people over time to identify risk factors that contribute to the development of these conditions. Preliminary results from this study have identified a series of clinical, psychological, sensory, genetic and nervous system factors that may increase the risk of having chronic TMJ disorders. These new findings expand our scientific understanding of the onset and natural course of TMJ disorders and may lead to new diagnostic and treatment approaches.
Additionally, researchers are using data from a TMJ implant registry and repository that collected health information from patients who received implants and from those who had implants removed. Recent studies using the data have helped researchers plan for new pain medication trials and other research projects.
Because pain is the major symptom of these conditions, NIH scientists are conducting a wide range of studies to better understand the pain process, including:
- understanding the nature of facial pain in TMJ disorders and what it may hold in common with other pain conditions, such as headache and widespread muscle pain,
- exploring differences between men and women in how they respond to pain and to pain medications,
- pinpointing factors that lead to chronic or persistent jaw joint and muscle pain,
- examining the effects of stressors, such as noise, cold and physical stress, on pain symptoms in patients with TMJ disorders to learn how lifestyle adjustments can decrease pain,
- identifying medications, or combinations of medications and conservative treatments, that will provide effective chronic pain relief,
- investigating possible links between osteoarthritis and a history of orofacial pain.
Modern Medical Language – Collins & Davis – ISBN 0-314-06702-7