What is TMJ disorder? Causes and Treatments

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Last updated November 20, 2021

What is TMJ?

This joint connects the mandibular fossa of the temporal bone, which is part of the skull, to the mandibular head of the mandible.


It is the only human joint in which the left and right joints move in tandem.

TMJ and Muscles

Between the mandibular fossa and the mandibular headarticular diskwhich moves in tandem with the movement of the TMJ and facilitates the smooth movement of the TMJ. In addition, the TMJ is a complex complex of cartilage, muscle tissue and fibrous tissue,

When the temporomandibular joint is affected by various causes, TMJ disorder occurs.

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Diagram of the temporomandibular joint

1) Causes of TMJ disorder

TMJ disorder has the following causesThe cause may be multiple.


There is no single cause. Are there any that apply?


Mental stress strains the muscles involved in the TMJ, causing pain and stiffness in the muscles themselves,The TMJ itself can become less mobile.

Grinding and clenching of teeth

Unintentional clenching or grinding of the teeth causes the teeth to wear down. This lowers the bite and puts strain on the jaw joints.

idiomatic habit

Habits that unconsciously place a burden on a part or the entire body are called body habits.

For example

Wearing a cheek cane, sleeping on your back, hunching over, etc....

Body habits can put stress on the TMJ and cause distortion.


Trauma to the TMJ itself, fractures as well as to the mandibular bodytransverse fracture(the mandibular head is fractured by an impact to the lower jaw) can also cause TMD.

Bite misalignment

If the bite of dentures or coverings is bad,Out of balance between the left and right bite and strain on the jaw jointsThis can cause TMJ disorder. This can cause TMJ disorder.

... partial mastication

If a tooth is missing on one side or if a tooth is present that causes pain when chewing, the patient will not bite in such an area.

This causes a bias in the way they chew.This can lead to increased stress on certain teeth, causing TMJ disorder.

(2) TMJ Symptoms


Here are the main symptoms of TMJ disorder. Do any of them apply to you?

interpoint (interword separation)have pain in the temporomandibular joint

interpoint (interword separation)The jaw joint moves.sometimes there is a sound

interpoint (interword separation)difficulty in opening one's mouth


If you have TMJ disorder...The area around the jaw may feel painful.

The TMJ itself may cause pain, but the muscles around the TMJ may feel sore.

Sound at opening or closing

The opening and closing movements areThe temporomandibular joint may make a "cracking" sound.

This is due to the cartilage (articular disc) that allows the joint to move smoothly having shifted from its normal position.

Oral opening disorder

If the TMJ is not moving properly, the mouth will not be able to move as it used to.It will not be able to open wide.

This can lead to pronunciation disorders and eating disorders.

(iii) Treatment of temporomandibular joint disorder

temporomandibular joint disorder

Opening training

If there is an opening disorder, open mouth training is performed. The opening training is a rehabilitation program that the patient performs on his or her own.

Methods of opening training

First, place your hand on the temporomandibular joint and move your jaw back and forth, back and forth, and side to side while sliding your upper and lower teeth.

At this time, repeat the movement of the left and right joints as much as possible so that the movement is the same on both sides.

2. next, in the same manner, place your hand on the temporomandibular joint and bring your lower jaw forward, then open your mouth as wide as possible.

This is also repeated so that the movement of the left and right joints is the same.

It is effective to do this several times a day, but it is more effective to do it while bathing, as the muscles around the TMJ are relaxed.

Muscle Massage

If there is pain in the muscles surrounding the TMJ, muscle massage can be used to relax the muscles.

The muscles that are often painful in TMJ disorder are the masseter and temporalis muscles.

Muscle Massage Methods

Place the index and middle fingers on the area of pain.

Rub the muscles while rotating your fingers in a circular motion, and after about 10 times

Perform about 10 counter-rotations as well.

As with mouth-opening training, it is more effective if performed during bathing, as the muscles around the TMJ are relaxed.

Articular Disc Positive Training

If you hear a "click" soundtrains the joint disc to return to its correct position.

training method

First, open the joint to the maximum amount and return the articular disk to the correct position.

Next, with the lower jaw protruding, the upper and lower teeth bite together.

3. pull the lower jaw back while sliding the upper and lower teeth.

If you pull back too far, the articular disk will move forward again, so try to pull back to the point where the articular disk does not move.

4. repeat this several times.

TMJ disorder and orthodontic treatment


As for whether TMJ disorder can be treated with orthodontic treatment,The conclusion is that it is difficult.

Orthodontic treatment can improve the bite, but it is not necessarily the only way to improve TMJ disorder.

This is because TMJ disorder may be related to many causes other than the bite.

TMJ symptoms that were not present before may also occur during orthodontic treatment.

If the pain is severe or otherwise interferes with daily life, we can respond by reducing the corrective force.

TMJ disorder and Invisalign Orthodontics


The use of Invisalign orthodontics to correct TMJ disorder, like any other orthodontic treatment, is not a panacea.

TMJ arthrosis caused by overbite, open bite, and other bites may be improved, but there is no guarantee that symptoms will improve.

Patients who have never had TMJ symptoms before may develop them after starting Invisalign orthodontic treatment.

Splint Therapy

Splint therapy is a treatment method in which a splint (mouthpiece) is worn in the mouth to stabilize the temporomandibular joint (TMJ) and to prevent stress on the TMJ from clenching or grinding the teeth.

The shape of the splint varies depending on the purpose of treatment.

The most commonly used type is the full-arch contact splint.

It is also called a stabilization-type splint. As the name implies, when the splint is worn, the upper and lower teeth are in even contact.

Distributes occlusal forces on some teeth,TMJ arthritis symptoms are reduced by relieving tension in the muscles that move the TMJ.

Drug Therapy

As an acute symptomIf you are in pain, or if the pain continues to be severelong (great, swinging) strideUse medicine.

Nonsteroidal anti-inflammatory drugs are often used as the first choice when acute symptoms are present.

In terms of specific product names,Loxonin and Voltarenis applicable.

Oral muscle relaxants are sometimes used for sore muscles to relieve muscle tension, but they have strong side effects and should be taken with caution.

If the pain persists, antidepressants or herbal medicines may be used.

Surgical Therapy

Surgery may be indicated when tissue adhesions or bone deformities are seen in the TMJ.

Basically, the surgery is performed in the oral surgery department of a large hospital.


TMJ disorder may have several causative factors.

If you have been diagnosed with TMJ disorder, it is important to start with treatment that is appropriate for your symptoms and cause.


First, see your family dentist.

imageWritten by dentist/issy

After graduating from the National School of Dentistry, he trained at the Tokyo Medical and Dental University Dental Hospital, and is currently working in general and orthodontic dentistry.

Member of the Japanese Society of Oral Implantology


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