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joint and muscle disorders, commonly called "TMJ," are a group of conditions
that cause pain and dysfunction in the jaw joint and the muscles that
control jaw movement. We don’t know for certain how many people have TMJ
disorders, but some estimates suggest that over 10 million Americans are
affected. The condition appears to be more common in women than men.
For most people, pain in
the area of the jaw joint or muscles does not signal a serious problem.
Generally, discomfort from these conditions is occasional and temporary,
often occurring in cycles. The pain eventually goes away with little or no
treatment. Some people, however, develop significant, long-term symptoms.
If you have questions
about TMJ disorders, you are not alone. Researchers, too, are looking for
answers to what causes these conditions and what are the best treatments.
Until we have scientific evidence for safe and effective treatments, it’s
important to avoid, when possible, procedures that can cause permanent
changes in your bite or jaw. This booklet provides information you should
know if you have been told by a dentist or physician that you have a TMJ
What is the temporomandibular joint?
The temporomandibular joint connects the
lower jaw, called the mandible, to the bone at the side of the head—the
temporal bone. If you place your fingers just in front of your ears and open
your mouth, you can feel the joints. Because these joints are flexible, the
jaw can move smoothly up and down and side to side, enabling us to talk,
chew and yawn. Muscles attached to and surrounding the jaw joint control its
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 jaw joint from chewing and other movements.
joint is different from the body’s other joints. The combination of hinge
and sliding motions makes this joint among the most complicated in the body.
Also, the tissues that make up the temporomandibular joint differ from other
load-bearing joints, like the knee or hip. Because of its complex movement
and unique makeup, the jaw joint and its controlling muscles can pose a
tremendous challenge to both patients and health care providers when
What are TMJ
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
Myofascial pain, the
most common temporomandibular disorder, involves discomfort or pain in
the muscles that control jaw function.
of the joint involves a displaced disc, dislocated jaw, or injury to the
Arthritis refers to a
group of degenerative/inflammatory joint disorders that can affect the
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. It is not known whether these
disorders share a common cause.
People who have a
rheumatic disease, such as rheumatoid arthritis, may develop TMJ disease 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. Both rheumatoid 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 causes TMJ disorders?
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. 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. Because the condition is more common in women than in men,
scientists are exploring a possible link between female hormones and TMJ
There is no scientific
proof that clicking sounds in the jaw joint lead to serious problems. In
fact, jaw clicking is 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.
The roles of stress and
tooth grinding as major causes of TMJ disorders are also unclear. Many
people with these disorders do not grind their teeth, and many long-time
tooth grinders do not have painful joint symptoms. Scientists note that
people with sore, tender chewing muscles are less likely than others to
grind their teeth because it causes pain. Researchers also found that stress
seen in many persons with jaw joint and muscle disorders is more likely the
result of dealing with chronic jaw pain or dysfunction than the cause of the
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 in the
face, jaw, or neck,
jaw muscle stiffness,
limited movement or
locking of the jaw,
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.
How are TMJ
There is no widely
accepted, standard test now available to correctly diagnose TMJ disorders.
Because the exact causes and symptoms are not clear, identifying these
disorders can be difficult and confusing. Currently, health care providers
note the patient’s description of symptoms, take a detailed medical and
dental history, and examine problem areas, including the head, neck, face,
and jaw. Imaging studies may also be recommended.
You may want to consult
your doctor to rule out known causes of pain. Facial pain can be a symptom
of many other conditions, such as sinus or ear infections, various types of
headaches, and facial neuralgias (nerve-related facial pain). Ruling out
these problems first helps in identifying TMJ disorders.
How are TMJ
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 is all that is usually needed 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),
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 doctor can
prescribe stronger pain or anti-inflammatory medications, muscle relaxants,
or anti-depressants to help ease symptoms.
Your doctor 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, stop using it and see your health care
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.
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
If you think
you have a TMJ disorder...
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 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. The findings may lead to a better understanding of the
onset and natural course of TMJ disorders and potentially to new diagnostic
and treatment approaches.
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:
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,
between men and women in how they respond to pain and to pain
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 adjusments can
medications, or combinations of medications and conservative treatments,
that will provide effective chronic pain relief,
possible links between osteoarthritis and a history of orofacial pain.
Research is also under
way to grow human tissue in the laboratory to replace damaged cartilage in
the jaw joint. Other studies are aimed at developing safer, more life-like
materials to be used for repairing or replacing diseased temporomandibular
joints, discs, and chewing muscles.
To learn more about TMJ
implants and their medical effects on patients, NIDCR has launched a TMJ
implant registry. The registry tracks the health of patients who receive
implants, as well as those who already have the devices, or who have had
them removed. Scientists also examine implants that have been removed to
learn why problems developed in these patients. By increasing understanding
of how temporomandibular joint implants perform and why they often fail, the
study will help scientists design safer and more effective implants. To
learn more about the TMJ implant registry, visit the registry website at
Hope for the
The challenges posed by
TMJ disorders span the research spectrum, from causes to diagnosis through
treatment and prevention. Researchers throughout the health sciences are
working together not only to gain a better understanding of the
temporomandibular joint and muscle disease process, but also to improve
quality of life for people affected by these disorders.