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You may have read
articles in newspapers and magazines about "TMD" -- temporomandibular (jaw)
disorders, also called "TMJ syndrome." Perhaps you have even felt pain sometimes
in your jaw area, or maybe your dentist or physician has told you that you
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 can we prevent
these disorders. The National Institute of Dental and Craniofacial Research
has written this pamphlet to share with you what we have learned about TMD.
TMD is not just
one disorder, but a group of conditions, often painful, that affect the
jaw joint (temporomandibular joint, or TMJ) and the muscles 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.
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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 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 TMJ from chewing and other movements.
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generally agre that temporomandibular disorders fall into three main categories:
pain, the most common form of TMD, which is discomfort or pain
in the muscles that control jaw function and the neck and shoulder muscles;
derangement of the joint, meaning a dislocated jaw or displaced
disc, or injury to the condyle;
joint disease, such as osteoarthritis or rheumatoid arthritis
in the jaw joint.
A person may have
one or more of these conditions at the same time.
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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.
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
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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:
- limited movement
or locking of the jaw,
- radiating pain
in the face, neck or shoulders,
- painful clicking,
popping or grating sounds in the jaw joint when opening or closing the
- a sudden, major
change in the way the upper and lower teeth fit together.
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
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Because the exact
causes and symptoms of TMD are not clear, diagnosing these disorders can
be confusing. At present, there is no widely accepted, standard test to
correctly identify TMD. In about 90 percent of cases, however, the patient's
description of symptoms, combined with a simple physical examination of
the face and jaw, provides information useful for diagnosing these disorders.
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.
X-rays and TMJ x-rays (transcranial radiographs) are not generally useful
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), are usually needed only when the
practitioner strongly suspects a condition such as arthritis or when significant
pain persists over time and symptoms do not improve with treatment. Before
undergoing any expensive diagnostic test, it is always wise to get another
One of the most
important areas of TMD research is developing clear guidelines for diagnosing
these disorders. Once scientists agree on what these guidelines should be,
it will be easier for practitioners to correctly identify temporomandibular
disorders and to decide what treatment, if any, is needed.
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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.
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 oral appliance, also called a splint or bite plate,
which is a plastic guard that fits over the upper or lower teeth. The splint
can help reduce clenching or grinding, which eases muscle tension. An oral
splint 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 practitioner.
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 into painful muscle sites,
often called "trigger points." Researchers are studying this type of treatment
to see if these injections are helpful over time.
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.
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.
Food and Drug Administration has recalled artificial jaw joint implants
made by Vitek, Inc., which may break down and damage surrounding bone. If
you have these implants, see your oral surgeon or dentist. If there are
problems with your implants, the devices may need to be removed.
treatments that are of little value -- and may make the problem worse --
include orthodontics to change the bite; restorative dentistry, which uses
crown and bridge work to balance the bite; and occlusal adjustment, grinding
down teeth to bring the bite into balance.
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.
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Keep in mind that
for most 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. Avoid,
if at all possible, treatments that cause permanent changes in the bite
or jaw. If irreversible treatments are recommended, be sure to get a reliable
especially dentists, are familiar with the conservative treatment of TMD.
Because TMD is usually painful, pain clinics in hospitals and universities
are also a good source of advice and second opinions for these disorders.
Specially trained facial pain experts can often be helpful in diagnosing
and treating TMD.
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NIH Consensus Program Information
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