Temporomandibular Joint Disorders (TMD)

Unlike a typical finger or vertebral junctions, each Temporomandibular Joint (TMJ) actually has two joints, which allows it to rotate and to translate (slide). With use, it is common to see wear of both the bone and cartilage components of the joint. Clicking is common, as are popping and deviations in the movements of the joint. Pain is the most conventional signifier of TMD.

In a healthy joint, the surfaces in contact with one another (bone and cartilage) do not have any receptors to transmit the feeling of pain. The pain therefore originates from one of the surrounding soft tissues, or from the trigeminal nerve itself, which runs through the joint area. When receptors from one of these areas are triggered, the pain can cause a reflex to limit the mandible’s movement. Furthermore, inflammation of the joints or damage to the trigeminal nerve can cause constant pain, even without movement of the jaw.

Due to the proximity of the ear to the temporomandibular joint, TMJ pain can often be confused with ear pain. The pain may be referred in around half of all patients and experienced as otalgia (earache). Conversely, TMD is an important possible cause of secondary otalgia.

Temporomandibular joint disorder (TMJD or TMD), or TMJ syndrome, is an umbrella term covering acute or chronic inflammation of the temporomandibular joint, which connects the mandible to the skull. The disorder and resultant dysfunction can result in significant pain and impairment. Because the disorder transcends the boundaries between several health-care disciplines — in particular, dentistry and neurology — there are a variety of treatment approaches.

The temporomandibular joint is susceptible to many of the conditions that affect other joints in the body, including ankylosis, arthritis, trauma, dislocations, developmental anomalies, and neoplasia.

An older name for the condition is “Costen’s syndrome”, after James B. Costen, who partially characterized it in 1934.

Signs and symptoms of temporomandibular joint disorder vary in their presentation and can be very complex, but are often simple. On average the symptoms will involve more than one of the numerous TMJ components: muscles, nerves, tendons, ligaments, bones, connective tissue, and the teeth. Ear pain associated with the swelling of proximal tissue is a symptom of temporomandibular joint disorder.

Symptoms associated with TMJ disorders may be:

•    Biting or chewing difficulty or discomfort
•    Clicking, popping, or grating sound when opening or closing the mouth
•    Dull, aching pain in the face
•    Earache (particularly in the morning)
•    Headache (particularly in the morning)
•    Hearing loss
•    Migraine (particularly in the morning)
•    Jaw pain or tenderness of the jaw
•    Reduced ability to open or close the mouth
•    Tinnitus
•    Neck and shoulder pain

Causes of TMD

There are many external factors that place undue strain on the TMJ. These include but are not limited to the following:

•    Bruxism (repetitive unconscious clenching or grinding of teeth, often at night).
•    Trauma
•    Malalignment of the occlusal surfaces of the teeth due to defective crowns or other restorative procedures.
•    Jaw thrusting (causing unusual speech and chewing habits).
•    Excessive gum chewing or nail biting.
•    Degenerative joint disease, such as osteoarthritis or organic degeneration of the articular surfaces, recurrent fibrous and/or bony ankylosis, developmental abnormality, or pathologic lesions within the TMJ
•    Myofascial pain dysfunction syndrome

Treatment

1. Restoration of the occlusal surfaces of the teeth
If the occlusal surfaces of the teeth or the supporting structures have been altered due to inappropriate dental treatment, periodontal disease, or trauma, the proper occlusion may need to be restored.

Patients with bridges, crowns, or onlays should be checked for bite discrepancies. These discrepancies, if present, may cause a person to make contact with posterior teeth during sideways chewing motions. These inappropriate contacts are called interferences, and if present, they can cause a patient to subconsciously avoid those motions, as they will provoke a painful response. The result can be excessive strain or even spasms of the chewing muscles.

2.Occlusal Splint
Occlusal splints (also called night guards or mouth guards) reduce nighttime clenching in some patients, while increasing clenching activity in other patients. Thus, while occlusal splints do prevent loss of tooth enamel from grinding, use of a splint can worsen TMJ disorder symptoms for some people.

3. Pain relief
While conventional analgesic pain killers such as paracetamol (acetaminophen) or NSAIDs provide initial relief for some sufferers, the pain is often more neurologic in nature, which often does not respond well to these drugs.

4. Jaw Exercises
Treatments for TMJ should not permanently alter the jaw or teeth, but need to be reversible. To avoid permanent change, over-the-counter or prescription pain medications may be prescribed. Some sufferers may also benefit from gentle stretching or relaxation exercises for the jaw, which may be recommended by their healthcare providers.

5. Surgery
Exercise protocols, habit control, and splinting should be the first line of approach, leaving oral surgery as a last resort. Certainly a focus on other possible causes of facial pain and jaw immobility and dysfunction should be the initial consideration of the examining oral-facial pain specialist, oral surgeon or health professional.

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