The Temporomandibular Joint (TMJ) or the jaw joint is a hinge-like joint connecting the lower jaw bone called mandible to the side of the skull bone, which is called the temporal bone. It is located just in front of the ear on either side of the face. The movement and position of the jaw are controlled by the muscles attached to it and those surrounding it. The joint and its muscles together enable us to chew, talk and yawn; TMJD interferes or disables these functions.
TMJD affects around 33% of the population. It particularly affects adults aged between 20 and 40 years. It is more common in females. Females more often present with symptoms of pain while symptoms like diminished jaw opening and chewing problems are more common in males.
Causes and Risk Factors of Temporomandibular Joint Dysfunction:
The exact cause of TMJD is unknown. Risk factors for developing the condition include:
► Myofascial pain dysfunction syndrome i.e. pain at the jaw joint due to increased muscle spasm or tension. This may be due to a physical cause or psychological stress.
► Structural derangement:
Trauma: Injury to the jaw can cause TMJ dysfunction. Trauma can also result from certain habits such as excessive clenching and grinding of teeth, biting nails or pencils, and chewing gums.
Genetic: The structural problems in the joint may be due to a genetic cause.
Disease conditions: Disease conditions and their treatments can result in TMJ dysfunction. These conditions include tumors, inflammation and infection, or radiation therapy.
► Degenerative joint disease: Individuals with degenerative joint diseases like rheumatoid arthritis and osteoarthritis may have a tendency to develop TMJD due to degeneration of articulating surfaces.
► Psychological factors: Psychological factors play an important role in the development of jaw pain, especially if the pain in muscular in origin.
Symptoms and Signs of Temporomandibular Joint Dysfunction:
Symptoms associated with TMJD include:
► Pain in the jaw joint associated with chewing, speaking and yawning. The pain can be on one side or both sides and may radiate to the ear, jaw, temple and neck. It is usually sudden in onset and resolves within 4–12 weeks. Sometimes, the condition can get chronic.
► Headache that may be dull, deep, continuous and usually worse over the course of the day.
► Limited jaw opening and side-to-side movement, joint clicking or grating sounds, ringing of ears (tinnitus), ear fullness and popping.
Diagnosis of Temporomandibular Joint Dysfunction:
Diagnosis of TMJD is based on:
► Patient History
► Physical Examination: Examination may reveal tenderness of joint or chewing muscles, clicking or grating sounds, and diminished mouth opening and side-to- side movement.
► Laboratory Tests: No specific laboratory studies are indicated.
General tests can be done, which include:
► Complete Blood Count, to detect possible infection.
► Rheumatoid factor if rheumatoid arthritis is suspected and Erythrocyte sedimentation rate, if temporal arteritis is suspected.
► Calcium, phosphate or alkaline phosphatase, to detect bone disease.
► Serum creatine and creatine phosphokinase, if muscle disorder is suspected.
► Serum uric acid, an indicator of gout disease.
► Imaging studies which include X-Ray, CT scan and MRI can detect structural deformities of the jaw. In addition they may also reveal the presence of fracture, disease conditions like osteoarthritis or articular displacement.
Treatment of Temporomandibular Joint Dysfunction:
Patients suffering from TMJ dysfunction should be treated promptly since it may become chronic over a course of time if left untreated. Treatment involves medications, physiotherapy, occlusal therapies, acupuncture and rarely surgery. Steroid injections into the joint may be necessary in some cases.
Medications used to treat the condition include:
► Analgesics - NSAIDs (Non-Steroidal Anti-inflammatory Drugs)
► Muscle Relaxants - Benzodiazepines
► Sedative and Hypnotics
► Botulinum Toxin and Capsaicin
Moist heat massage of the jaw and physiotherapy helps to manage the condition. Also, it is sometimes necessary to relieve psychological stress by practicing yoga, meditation, hypnosis and relaxation. It is equally necessary, to maintain good dental hygiene to prevent oral infection and inflammation.