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What is The TMJ?
The temporomandibular joint (TMJ) is the point where the lower jaw, composed of the mandible, and the temporal bone of the skull are joined, forming a movable joint in front of the ear. It is a powerful joint that allows the mouth to open and chewing, talking, yawning and other movements of the lower jaw to take place. Its movement is powered by the dynamic muscles of the cheeks, which are innervated by the trigeminal nerve.
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Disorders of the TMJ
TMJ disorders may be a result of trauma to the face and jaw, arthritic conditions or simple muscle spasms, as in jaw clenching or grinding of the teeth. Disorders affecting the joint itself are called internal derangements and may be the result of fractures, dislocations, tumors or degenerative changes in the bones and joint. A few cases are related to other diseases that affect bones and joints, such as Sjogren's syndrome.
Some disorders may originate from the muscles and ligaments around the joint, in which case they are called Myofascial Pain Syndrome (MPS).
Because of the many possible causes of TMJ disorder, diagnosis may not be easy.
Disorders of the TMJ result in pain, limitation of movement and, in some instances, locking of the jaw. Symptoms of TMJ disorders include:
- Clenching and grinding the teeth
- Jaw pain, which may be felt at the side of the face, around the cheek, in front of the ear or near the temple; pain may be one-sided or bilateral
- Pain or difficulty while chewing, opening the mouth and yawning
- Sore teeth, especially in the morning
- Jaws popping, clicking and locking during mouth opening
- Persistent headaches and neck pain
Diagnosis of TMJ disorders may be obtained from the history and physical examination or by laboratory exams, particularly radiologic imaging. X-ray, CT scan, MRI and arthrography are useful in evaluating the jaw. Arthroscopy, an endoscopic procedure to explore the area inside the jaw may also be performed, to take pictures and evaluate or diagnose the disorder.
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Arthroscopic Surgery for TMJ
Medical management using pain relievers, antibiotics and other drugs is usually effective in treating most disorders of the temporomandibular joint and its surrounding structures. Other modalities of treatment include physical therapy, diet modification, stress management and hypnosis. Very few patients will actually need open surgery. Furthermore, an alternative to conventional surgery exists, and this is arthroscopic surgery, which is far less invasive.
In arthroscopic TMJ surgery, a small (around 3 cm) incision is made to allow a fiber optic camera to pass through the skin and examine the joint and its surrounding structures. The surgeons are able to visualize the operating field on a screen, while inserting and manipulating instruments through the opening. In this procedure an accurate diagnosis can be made, at the same time allowing immediate treatment, which may include repair of ligaments, muscles, nerves and joints. Rinsing of the tissues (lavage) may also be performed during the operation.
The procedure can last up to three hours, after which the patient will be allowed to recover from anesthesia. He may then go home with a companion and will be able to drink and eat a soft diet. Full recovery usually takes one to three weeks and, depending on the TMJ disorder, he may need physical therapy for full jaw function.
Because of the simplicity of the procedure, arthroscopy has many benefits, compared to conventional surgery, such as:
- Less bleeding and infection
- Smaller incision, less scarring
- May be done on an out-patient basis, so patient can go home within hours of the operation
- Less post-operative pain and fewer complications
The risks of this procedure are similar to any surgery, and the most common is failure to alleviate symptoms. Other risks and complications include bleeding, infection and injury to nerve.
Many conditions affecting the muscles, ligaments and bones of the jaw can be treated medically; however, there are a few conditions which do not respond to medical therapy and may require surgery. Arthroscopy is a simple and safe mode of treatment for severe pain and dysfunction of the jaw.
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The University of Texas Medical Branch, “Temporomandibular Joint Disorders," accessed 12/08/10
New York-Presbyterian Hospital, "Arthroscopy for Temporomandibular Joint Disorders" 12/08/10