Although no specific data exists regarding the social impact of temporamandibular joint disorders, TMJ is estimated to account for as much as thirty billion dollars a year in lost productivity. Americans lose 550 million work days every year due to symptoms associated with TMJ, with facial pain and headache being the most common complaints. Accordingly, analgesics directed at these symptoms are among the top selling over the counter medicines in our society.
Despite the lack specific data regarding the incidence of these disorders, much has been learned over the last decade regarding specific pathology and therapy. Generic terms such as TMJ Syndrome, or Myofascial Pain Dysfunction Syndrome (MPD Syndrome) are generally outdated. It is now possible to differentiate between true muscular disorders and those disorders with pathological changes of the temporomandibular joint.
The term temporomandibular joint disorders is an umbrella term which combines those with true pathology of the temporomandibular joint and those with involvement of the muscles of mastication (myofascial pain dysfunction). Much of the difficulty encountered with the treatment of these patients is attributed to the physicians inability to accurately diagnose the disorder.
Diseases and Disorders of the TMJ
The temporomandibular joint is susceptible to all the conditions that affect other joints in the body, including ankylosis, arthritis, trauma, dislocations, developmental anomalies and neoplasms. Although treatment is often similar to other joints in the body, some variations exist.
Myofascial pain disorders are the most common cause of pain in the head and neck, and those involved in the temporomandibular joint are no exception. The complex symptomatology and frequent psychosocial factors often make these disorders difficult to treat. Once diagnosed, however, treatment is usually effective if compliance is maintained. The muscles of mastication are primarily involved, and the condition is characterized by a unilateral dull, aching pain which increases with muscular use. Common complaints associated with referred pain include headache, otalgia, tinnitus, burning tongue and sometimes decreased hearing.
There is believed to be a large psychosocial component of this disease. Increased stress levels are believed to result in poor habits, including bruxism, clenching and even excessive gum chewing. These lead to muscular overuse, fatigue and spasm, and subsequently, pain.
Muscular disorders consist of a group of diagnoses that are characterized by pain from pathologic or dysfunctional changes in a muscle group, and there are at least six recognized disorders of the head and neck. Myositis is an acute condition with inflammation of the muscle and connective tissue with associated pain and edema and a decreased range of motion. Etiologies include overuse, infection or trauma. Muscle spasm is considered an acute contraction of a muscle caused by an overstretching or overuse of a muscle. If left untreated in the contracted state, fibrous scarring and contracture will develop. Hysterical trismus refers to decreased range of motion which is due to psychological causes. Fibromyalgia is a diffuse, systemic muscular process whereby areas of firm, painful bands are found in weight bearing muscles, often with an associated sleep disorder. There is no evidence of arthritis or myositis, and there is a female preponderance. There is often associated bruxism and arthritis, and the most common areas affected are the back, head and neck, abdomen and extremities.
Myofascial pain syndrome (MPS) may be considered a localized form of fibromyalgia in the head and neck. There are three diagnostic criteria:
the presence of painful, firm bands of muscle or tendons, termed trigger points;
pain complaints that follow known patterns of referral of trigger points, and
reproducible pain complaints with trigger points.
Collagen diseases such as systemic lupus erythematosis, Sjogrens syndrome, scleroderma and arthritis also cause muscular pain in the head and neck. Lupus is characterized by a butterfly rash of the face, fever, rheumatoid arthritis and pleural and abdominal pain. Laboratory studies reveal a high sedimentation rate, hypochromic anemia, a positive ANA test and a false-positive VDRL. Scleroderma is characterized by gradual onset of muscle and joint pain leading to a systemic sclerosis with anorexia, dyspnea and diminished sweating. Fever, skin lesions and limited jaw and chest expansion are seen.
Sjogren's syndrome is characterized by dryness of the mouth, eye and skin and oftentimes, muscle and joint pain. Rheumatoid arthritis is a chronic inflammation of the synovial membrane with pain in the muscles and joints. Numerous joints in the body are usually affected, and pain usually decreases with use. Fatigue, fever, muscle pain, night sweats and sometimes weight loss are seen. Studies show the presence of rheumatoid factor, and increased sedimentation rate and antinuclear antibodies.
The treatment of myofascial pain is divided into four phases. Read More...