The temporomandibular joint (TMJ) connects your lower jaw (mandible) to your skull, located just in front of each ear. This joint facilitates essential movements like chewing, speaking, and yawning. A TMJ dislocation occurs when the jawbone moves out of its normal position within this joint.
Understanding TMJ Dislocation
During a TMJ dislocation, the condyle (the rounded end of the jawbone) moves forward beyond the temporal bone’s articular eminence. This displacement can cause the jaw to lock in an open position. The TMJ is a complex structure involving the mandibular condyle, the temporal bone’s glenoid fossa, and an articular disc. This fibrous disc cushions the joint, enabling both hinging and gliding motions.
Dislocations are classified by presentation. An acute dislocation is a first-time or isolated incident. Chronic dislocations occur when an acute dislocation remains unreduced for an extended period.
Chronic recurrent dislocations involve frequent episodes where the jaw easily dislocates, often during everyday activities. Anterior dislocations, where the condyle moves forward, are the most common. Posterior, superior, and lateral dislocations can also occur, usually from trauma.
Causes and Symptoms
TMJ dislocations often arise from extreme jaw movements. Common causes include wide yawning, forceful laughing, or taking an excessively large bite. Dental procedures requiring prolonged mouth opening, such as extractions or intubation, can also trigger a dislocation. Trauma to the jaw, like a direct blow, is another potential cause.
Underlying conditions can increase the likelihood of dislocation. Individuals with hypermobility, where joint ligaments are unusually loose, are more susceptible. Certain connective tissue or neurological conditions may also increase this predisposition. Immediate symptoms include an inability to close the mouth, a sensation that the jaw is locked open, and significant pain around the jaw and ear. The jaw may also appear visibly shifted or lopsided, making speaking and chewing difficult.
Treatment and Management
Immediate treatment for an acute TMJ dislocation involves manual reduction, where a healthcare professional repositions the jaw. This technique applies downward and backward pressure on the back molars to guide the condyle back into position. Prompt treatment is important, as muscle spasms can worsen, making reduction more challenging. Sedation or local anesthesia may be used to relax muscles and minimize discomfort.
For recurrent or chronic dislocations, non-surgical strategies are often employed. Physical therapy includes exercises to stretch jaw muscles and improve joint mobility. Custom oral appliances, such as splints or bite guards, can stabilize the jaw and reduce joint stress. Medications, including pain relievers, anti-inflammatory drugs, or muscle relaxants, help manage pain and muscle spasms. Injections, such as botulinum toxin into the lateral pterygoid muscles, can temporarily reduce muscle strength and prevent recurrent dislocations.
If conservative approaches are unsuccessful, surgical interventions may be considered for persistent or severe cases. An eminectomy involves reshaping or removing the articular eminence to allow the condyle to move freely. Capsular plication tightens ligaments around the joint for greater stability. These surgical methods aim to either facilitate easier movement or restrict excessive movement, depending on the specific cause of recurrence.
Preventing Recurrence
To prevent future TMJ dislocations, individuals can adopt several measures. Avoiding extreme jaw movements is advised, such as refraining from wide yawning or taking excessively large bites. When yawning, supporting the jaw with a hand can limit its range of motion.
Managing underlying conditions that contribute to joint hypermobility is also important. Adherence to prescribed jaw exercises, often taught by a physical therapist, can strengthen surrounding muscles and improve joint stability. Consistent use of custom splints or bite guards, if recommended, can help maintain proper jaw alignment and reduce dislocation risk during sleep or clenching.