Temporomandibular joint disorder

Temporomandibular joint disorder
Classification and external resources
File:Gray309.png Temporomandibular joint
ICD-10	K07.6
ICD-9	524.60
DiseasesDB	12934
MedlinePlus	001227
eMedicine	neuro/366 radio/679 emerg/569
MeSH	C05.500.607.221.897.897

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 syndrome", named for the man 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)
• 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

Temporomandibular joints

Unlike typical finger or vertebral junctions, each 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 it. Clicking is common, as are popping and deviations in the movements of the joint. Pain is the most conventional signifier of TMJ.

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. Treatment of TMD may then significantly reduce symptoms of otalgia and tinnitus, as well as atypical facial pain. Despite some of these findings, some researchers question whether TMD therapy can reduce symptoms in the ear, and there is currently an on going debate to settle the controversy.

The dysfunction involved is most often in regards to the relationship between the condyle of the mandible and the disc. The sounds produced by this dysfunction are usually described as a "click" or a "pop" when a single sound is heard and as "crepitation" or "crepitus" when there are multiple, rough sounds.

Teeth

Disorders of the teeth can contribute to TMJ dysfunction. Impaired tooth mobility and tooth loss can be caused by destruction of the supporting bone and by heavy forces being placed on teeth. The movement of the teeth affects how they contact one another when the mouth closes, and the overall relationship between the teeth, muscles, and joints can be altered. Pulpitis, inflammation of the dental pulp, is another symptom that may result from excessive surface erosion. Maybe the most important factor is the way the teeth meet together: the equilibration of forces of mastication and therefore the displacements of the condyle. Many report TMJ dysfunction after having their wisdom teeth extracted.

Cause

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

Over-opening the jaw beyond its range for the individual or unusually aggressive or repetitive sliding of the jaw sideways (laterally) or forward (protrusive). These movements may also be due to parafunctional habits or a malalignment of the jaw or dentition. This may be due to:

1. Trauma
2. Bruxism (repetitive unconscious clenching or grinding of teeth, often at night).
3. Malalignment of the occlusal surfaces of the teeth due to dental defect or neglect.
4. Jaw thrusting (causing unusual speech and chewing habits).
5. Excessive gum chewing or nail biting.
6. Size of food bites eaten.
7. 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
8. Myofascial pain dysfunction syndrome
9. Lack of overbite

Patients of TMJ often experience pain such as migraines or headaches, and consider this pain TMJ-related. There is some evidence for this in that more than 50% of people who use nighttime biofeedback to reduce nighttime clenching experience a significant reduction in migraines and headaches as well as a reduction in direct TMJ pain. While TMJ disorder is a possible cause of migraines and headaches, other causes should also be considered. E.g.

• Cervical Spondylosis
• Migraine
• Etc.

Treatment

Restoration of the occlusal surfaces of the teeth

If the occlusal surfaces of the teeth or the supporting structures have been damaged due to dental neglect, periodontal diseases or trauma, the proper occlusion should be restored. E.g. Patients with bridges/crowns should be checked for improper height of the dental work, which could result in misalignment of the top and bottom teeth. Occlusal restoration reduces TMJ symptoms for some patients.

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.

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.

An alternative approach is for pain modification, for which off-label use of low-doses of Tricyclic antidepressant that have anti-muscarinic properties (e.g. Amitriptyline or the less sedative Nortriptyline) generally prove more effective. In TMJD the muscles are unbalanced. Biofeedback using EMG is successful in balancing these muscles. A mirror can be used as a biofeedback device: Draw a vertical line on mirror. Relax the jaw by relaxing as you exhale. See the jaw relax in the midline. Practice the breathing and relaxing daily using the mirror. When the jaw does open midline the symptoms should abate.

Long-term approach

It is suggested that before the attending dentist commences any plan or approach using medications or surgery, a thorough search for inciting para-functional jaw habits must be performed. Correction of any discrepancies from normal can then be the primary goal.

Patients may employ a nighttime biofeedback instrument such as a biofeedback headband to help them modify para-functional jaw habits which take place in sleep. In addition, there are various treatment modalities which a well-trained experienced dentist may employ to relieve symptoms and improve joint function. They include:

• Manual adjustment of the bite by grinding the teeth (occlusal adjustment). This, too, is not a widely accepted practice and should be avoided as it is irreversible.
• Nighttime biofeedback for para-functional habit modification
• Mandibular repositioning splints which move the jaw, ligaments and muscles into a new position and myofunctional therapy
• Reconstructive dentistry
• Orthodontics
• Arthrocentesis (joint irrigation)
• Surgical repositoning of jaws to correct congenital jaw malformations such as prognathism and retrognathia
• Replacement of the jaw joint(s) or disc(s) with TMJ implants (This should be considered only as a treatment of last resort.)

Elimination of para-functional habits

An approach to eliminating para-functional habits involves the taking of a detailed history and careful physical examination. The medical history should be designed to reveal duration of illness and symptoms, previous treatment and effects, contributing medical findings, history of facial trauma, and a search for habits that may have produced or enhanced symptoms. Particular attention should be directed in identifying perverse jaw habits, such as clenching or teeth grinding, lip or cheek biting, or positioning of the lower jaw in an edge-to-edge bite. All of the above strain the muscles of mastication (chewing) and results in jaw pain. Palpation of these muscles will cause a painful response.

Treatment is oriented to eliminating oral habits, physical therapy to the masticatory muscles, and alleviating bad posture of the head and neck. A biofeedback headband may be worn at night to help patients train themselves out of the para-functional habit of nighttime clenching and grinding (bruxism). A flat-plane full-coverage oral appliance, e.g. a non-repositioning stabilization splint, reduces bruxism in some patients, and can take stress off the temporomandibular joint, although some individuals may bite harder on it, resulting in a worsening of their conditions. The anterior splint, with contact at the front teeth only, may prove helpful to some patients, but for those patients who bite harder on this type of splint, even more damage may occur. Thus, different types of splint therapy may work for different patients.

Reversible treatments

According to the National Institute of Dental and Craniofacial Research (NIDCR) of the National Institutes of Health (NIH), TMJ treatments should be reversible whenever possible. That means that the treatment should not cause permanent changes to the jaw or teeth. Examples of reversible treatments are:

• Over-the-counter pain medications, used according to manufacturers' instructions.
• Prescription medications prescribed by a healthcare provider.
• Gentle jaw stretching and relaxation exercises you can do at home. Your healthcare provider can recommend exercises for your particular condition, if appropriate.
• Feldenkrais TMJ Program, uses a unique understanding of human neurology to reduce chronic tension in the jaw, face, neck, and upper back, and to reverse long-standing movement habits responsible for the original TMJ symptoms.
• Stabilization splint (biteplate, nightguard) is the most widely used treatment for TMJ and jaw muscle problems; however, the actual effectiveness of these splints is unclear. If an oral 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 tell your healthcare provider. Avoid using over-the-counter mouthguards for TMJ treatment. If a splint is not properly fitted, the teeth may shift and worsen the condition.
• Mandibular Repositioning (MORA) Devices can be worn for a short time to help alleviate symptoms related to painful clicking when opening the mouth wide, but 24-hour wear for the long term may lead to changes in the position of the teeth that can complicate treatment. A typical long-term permanent treatment (if the device is proven to work especially well for the situation) would be to convert the device to a flat-plane bite plate fully covering either the upper or lower teeth and to be used only at night. According to an article on Quackwatch.org, MORA devices are considered the most widely used option although the scientific validity has not been proven.

Surgery

Attempts in the last decade to develop surgical treatments based on MRI and CAT scans now receive less attention. These techniques are reserved for the most recalcitrant cases where other therapeutic modalities have changed. 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.

One option for oral surgery, is to manipulate the jaw under general anaesthetic and wash out the joint with a saline and anti-inflammatory solution in a procedure known as arthrocentesis. In some cases, this will reduce the inflammatory process.

Jaw dislocation

Main article: Dislocation of jaw

The jaw can dislocate if a person opens their mouth too wide, particularly when a person attempts to open the jaw widely in an effort to stretch the facial muscles i.e. to relieve tense facial muscles as the wisdom teeth develop and emerge.

The jaw can also "slide out" as the person is sleeping on their side.

See also

• Bruxism

References

• Okeson, Jeffrey P. (2003). Management of temporomandibular disorders and occlusion (5th ed.). St. Louis: Mosby. ISBN 0-323-01477-1. 

External links

• Temporomandibular joint disorder at the Open Directory Project

ca:Trastorn de l'articulació temporomandibular pt:Disfunção temporomandibular e dor orofacial