Temporomandibular Joint (TMJ) Syndrome (cont.)
TMJ Syndrome Causes
TMJ syndrome can be caused by trauma, disease, wear
due to aging, or habits.
- Trauma: Trauma is divided into microtrauma and macrotrauma. Microtrauma is internal, such as bruxism (grinding
the teeth) and clenching (jaw tightening). This continual hammering on the
temporomandibular joint can change the alignment of the teeth. Muscle
involvement causes inflammation of the membranes surrounding the joint. Teeth
grinding (bruxism) and clenching are habits that may be diagnosed in people
who complain of pain in the temporomandibular joint or have facial pain that
includes the muscles involved in chewing (myofascial pain). Macrotrauma, such
as a punch to the jaw or impact in an accident, can break the jawbone or
damage the disc.
- Bruxism: Teeth grinding as a habit can result in
muscle spasm and inflammatory reactions, thus causing the initial pain. Changes in the normal stimuli or height of the teeth, misalignment of the teeth, and changes in the chewing muscles may cause temporomandibular joint changes. Generally, someone who has a habit of grinding his or her teeth will do so mostly during sleep. In some
cases, the grinding may be so loud that it disturbs others.
- Clenching: Someone who clenches continually bites on things while awake. This might be chewing gum, a pen or pencil, or fingernails. The constant pounding on the joint causes the pain. Stress is often blamed for tension in the jaw,
leading to a clenched jaw.
- Osteoarthritis: Like other
joints in the body, the jaw joint is prone to undergo arthritic changes. These changes are sometimes caused by breakdown of the joint (degeneration) or normal aging. Degenerative joint disease causes a slow progressive loss of cartilage and formation of new
bone at the surface of the joint. Cartilage destruction is a result of several
mechanical and biological factors rather than a single entity. Its prevalence
increases with repetitive microtrauma or macrotrauma, as well as with normal
aging. Immunologic and inflammatory diseases contribute to the progress of the
disease.
- Rheumatoid arthritis: Rheumatoid arthritis causes inflammation in joints and can affect the TMJ, especially in children. As it progresses, the disease can cause destruction of cartilage and erode bone, deforming joints. It is an autoimmune disease involving the antibody factor against immunoglobulin G
(IgG). Chronic rheumatoid arthritis is a multisystem inflammatory disorder with persistent symmetric joint inflammation.
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