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Temporomandibular joint disorder
Temporomandibular joint disorder (TMJD, TMJ or TMD), or TMJ syndrome, is an umbrella term covering acute or chronic inflammation of the temporomandibular joint, which connects the lower jaw 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, neurology, physical therapy, and psychology — there are a variety of quite different 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.
Additional recommended knowledge
Signs and symptoms
Signs and symptoms of temporomandibular joint disorder vary in their presentation and can be very complex. Often the symptoms will involve more than one of the numerous TMJ components: muscles, nerves, tendons, ligaments, bones, connective tissue, and the teeth.
Disorders of the muscles of the temporomandibular joint are the most common complaints by TMD patients. The two major observations concerning the muscles are pain and dysfunction. The dysfunction can present as trismus or limitation of jaw movement ranging from minor to severe. In milder cases, the only representation may be joint sound such as clicking or popping. These symptoms of TMD are often caused by overusage of the muscles of mastication. Common causes include chewing gum continuously, biting habits (fingernails and pencils), grinding habits, and clenching habits.
Most cases of TMJ, however, are not so simple. Deep-space infections with resulting trismus or neoplams about the joint may mimic TMJ dysfunction. Muscle pain can sometimes be associated with trigger points in muscle tissue. These trigger points can be localized by digital palpation, both intraorally and extraorally. This is known as Myofascial pain syndrome.
Any dysfunction of the muscles may cause the teeth to occlude (bite) with each other incorrectly;if teeth are traumatized by this, they may become sensitive, demonstrating one of the many interplays between muscle, joint, and tooth.
This is arguably the most complex set of joints in the human body. Unlike typical finger or vertebral junctions, each TMJ actually has two joints, which allow it to both 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 motions and deviations in the movements of the joint. It is considered a TMJ disorder when pain is involved.
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. When receptors from one of these areas are triggered, the pain causes a reflex to limit the mandible's movement. Furthermore, inflammation of the joints can cause constant pain, even without movement of the jaw.
Due to close 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 ongoing 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.
Disorders of the teeth can contribute to TMJ dysfunction. Tooth mobility and tooth loss can be caused by destruction of the supporting bone and by heavy forces being placed on teeth. 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.
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:
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.
While conventional analgesic pain killers such as paracetamol or NSAIDs provide initial relief for some sufferers, the pain is often more neuralgic 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.
It is suggested that before the attending dentist commences any plan or approach utilizing 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.
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 flat-plane full-coverage oral appliance, e.g. a non-repositioning stabilization splint, often is helpful to control bruxism and 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 then prove helpful.
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:
What may be concluded is that there are various treatment modalities which a well-trained experienced dentist may employ to relieve symptoms and improve joint function. They include:
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.
|This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Temporomandibular_joint_disorder". A list of authors is available in Wikipedia.|