Temporomandibular joint and muscle disorders (TMJ disorders) are problems that affect the chewing joints and muscles that connect the lower jaw to the skull.

Causes
There are 2 paired temporomandibular joints, one on each side of the head, located just in front of the ears. The abbreviation “TMJ” literally refers to the name of the joint, but is often used to refer to any disorder or symptom of this region.

Many TMJ-related symptoms are caused by effects of physical stress on the structures around the joint. These structures include:

Cartilaginous disc in the joint
Muscles of the jaw, face, and neck
Nearby ligaments, blood vessels, and nerves
Teeth
For many people with temporomandibular joint disorders, the cause is unknown. Some causes given for this condition have not been well proven. They include:

A bad bite or orthodontic appliances.
Stress and teeth grinding. Many people with TMJ problems do not grind their teeth and many who have been grinding their teeth for a long time do not have problems with their TMJ. For some people, the stress associated with this disorder may be causing the pain rather than being the cause of the problem.
Poor posture can also be a major factor in TMJ symptoms. For example, holding your head forward all day while looking at a computer strains the muscles in your face and neck.

Other factors that may worsen TMJ symptoms are poor diet and lack of sleep.

Many people end up having “trigger points” – muscle contraction in the jaw, head and neck. These trigger points can refer pain to other areas causing headache, earache or toothache.

Other possible causes of TMJ-related symptoms include arthritis, fractures, dislocations and structural problems present at birth.

Symptoms
Symptoms associated with temporomandibular joint disorders may include:

Difficulty or discomfort when biting or chewing
Clicking or popping when opening or closing the mouth
Dull facial pain in the face
Ear pain
Headache
Jaw pain or tenderness
Jaw locking
Difficulty opening or closing the mouth
Tests and exams
You may need to see more than one specialist for TMJ pain and symptoms. This may include a health care provider, a dentist, or an ear, nose, and throat specialist, depending on your symptoms.

You will need a complete examination involving:

A dental examination that can show if you have bite misalignment.
Palpate the joints and muscles for tenderness.
Press around the head to locate tender or painful areas.
Slide the teeth from side to side.
Watch, feel and listen when opening and closing the jaw.
X-rays, CT scan, MRI, Doppler testing of the TMJ.
Sometimes, physical examination results may appear normal.

Your provider will also need to consider other conditions, such as infections, nerve-related problems, ear infections and headaches, that may be causing your symptoms.

Treatment
Simple and gentle therapies are usually recommended first.

Soft diet to soothe joint swelling.
Learn how to stretch, relax or gently massage the muscles around your jaw. Your provider, dentist or physical therapist can help you with this.
Avoid actions that cause symptoms, such as yawning, singing and chewing gum.
Try wet, cold or hot compresses on your face.
Learn techniques to reduce stress.
Exercising several times each week can help increase your ability to manage pain.
Bite analysis
Read as much as you can about how to treat TMJ disorders, as opinions vary widely. Seek opinions from several providers. The good news is that most people eventually find something that helps them.

Ask your provider or dentist about medications you can use. These may include:

Short-term use of acetaminophen, ibuprofen, or naproxen (or other nonsteroidal anti-inflammatory drugs)
Muscle relaxants or antidepressants
Injections of muscle relaxants such as botulinum toxin
Rarely, corticosteroid injections into the TMJ to treat inflammation
Mouth or bite guards, also called splints or braces, have long been used to treat teeth grinding and clenching, as well as TMJ disorders. They may or may not help.

Although many people have found them to be helpful, the benefits vary widely. The guard may lose its effectiveness over time or when the person stops wearing it. Others may feel worse pain when wearing them.
There are different types of splints, some of which fit over the upper teeth, while others fit over the lower teeth.
Permanent use of these items may not be recommended. You should also discontinue them if they cause any changes in your bite.
If conservative treatments do not work, it does not automatically mean that you need more aggressive treatment. Be cautious about contemplating an irreversible treatment method, such as orthodontics or surgery that permanently changes your bite.

Rarely is reconstructive surgery or jaw arthroplasty required. In fact, the results are often worse than before surgery.

Information taken from: https://medlineplus.gov/spanish/ency/article/001227.htm