DISORDERS

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES

National Institutes of Health

TMJ
What Is the 

Temporomandibular Joint?

What Are 

TMJ Disorders?

What Causes 

TMJ Disorders?

What Are the 

Signs and Symptoms?

How Are TMJ 

Disorders Diagnosed?

How Are TMJ 

Disorders Treated?

If You Think You 

Have a TMJ Disorder...

Research

Hope for the Future

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4

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contents
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TMJ DISORDERS

Temporomandibular 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 

disorder. 
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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.

The temporomandibular 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 loadbearing 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 problems arise.
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Temporal muscle covering 

temporal bone

Disc

Condyle

Masseter muscle

Mandible

open

closed
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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:

1 Myofascial pain, the most common 

temporomandibular disorder, involves 

discomfort or pain in the muscles that 

control jaw function.

2 Internal derangement of the joint involves 

a displaced disc, dislocated jaw, or injury 

to the condyle.

3 Arthritis refers to a group of degenerative/

inflammatory joint disorders that can affect 

the temporomandibular joint.

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.
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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.

 TMJ
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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 

disorders.

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 condition.
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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:

n radiating pain in the face, jaw, or neck,

n jaw muscle stiffness,

n limited movement or locking of the jaw,

n painful clicking, popping or grating in 

the jaw joint when opening or closing 

the mouth, 

n a change in the way the upper and lower 

teeth fit together.

 TMJ
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How Are TMJ 

Disorders Diagnosed?

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.
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How Are TMJ 

Disorders Treated?

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.

Conservative Treatments

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.

Self-Care Practices

There are steps you can take that may be 

helpful in easing symptoms, such as:

n eating soft foods, 

n applying ice packs,

n avoiding extreme jaw movements 

(such as wide yawning, loud singing, 

and gum chewing), 

 TMJ
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n learning techniques for 

relaxing and reducing stress,

n 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.

Pain Medications

For many people with TMJ disorders, shortterm 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 antidepressants to help ease symptoms. 

Stabilization Splints

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 provider.
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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

BotoxTM (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. The Food and Drug 

Administration (FDA) has approved Botox for 

the treatment of certain eye muscle disorders, 

cervical dystonia (neck muscle spasms), and 

severe underarm sweating, as well as for 

limited cosmetic use. Botox has not been 

approved by the FDA for use in TMJ disorders. 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

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.

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Surgery

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.

Implants

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.
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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.

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, 

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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.

Research

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. 

Pain Studies

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:

n 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,
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n exploring differences between men and 

women in how they respond to pain and 

to pain medications,

n pinpointing factors that lead to chronic or 

persistent jaw joint and muscle pain,

n 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,

n identifying medications, or combinations 

of medications and conservative treatments, that will provide effective chronic 

pain relief,

n investigating possible links between 

osteoarthritis and a history of orofacial 

pain.

Replacement Parts

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.

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Implant Registry

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 http://tmjregistry.org.

Hope for the Future

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.
 TMJ

TMJ DISORDERS is produced and 

distributed by the National Institute of 

Dental and Craniofacial Research in 

partnership with the Office of Research 

on Women’s Health, components of the 

National Institutes of Health 

(NIH) in Bethesda, Maryland. Part of 

the U.S. Department of Health and 

Human Services, NIH is one of the 

world’s foremost medical research 

centers and the Federal focal point for 

medical research in the United States.
For additional copies of this pamphlet contact:

National Institute of Dental and Craniofacial Research

National Oral Health Information Clearinghouse

1 NOHIC Way

Bethesda, MD 20892-3500

1–866–232–4528

www.nidcr.nih.gov

This publication is not copyrighted. 

Make as many photocopies as you need.

NIH Publication No. 10-3487 Revised March 2010