Temporomandibular joint (TMJ) dislocation generally occurs in predisposed individuals after a vigorous yawn or seizure, or less commonly from direct trauma to the chin while the mouth is open. Dislocation occurs when the mandibular condyles displace forward and become locked anterior to the articular eminence. Masseter muscle spasm contributes to prevention of spontaneous relocation. Weakness of the temporomandibular ligament, an overstretched joint capsule, and a shallow articular eminence are predisposing factors. Patients usually present with an inability to close an open mouth. Other associated symptoms include pain, discomfort, facial swelling near the TMJ, and difficulty speaking and swallowing. Anterior dislocations are most common; however, posterior dislocation may occur with significant trauma, often in association with basilar skull fractures. Unilateral dislocation results in deviation of the mandible to the unaffected side. TMJ hemarthrosis and dystonic reactions may mimic TMJ dislocations. Mandibular fractures should be considered if there is a history of facial trauma.
TMJ Dislocation (Bilateral). This patient awoke from sleep with the inability to close her mouth. Note the dry lips and tongue secondary to prolonged exposure. (Photo contributor: Warren K. Russell, MD.)
Management and Disposition
Acute reduction of pain, muscle spasm, and anxiety is achieved using reassurance, analgesics, and benzodiazepine muscle relaxants. Panorex or TMJ x-ray films (prereduction and postreduction) should be considered to exclude a fracture. A reduction maneuver is performed while facing the sitting patient and grasping the angles of the mandible with both hands. The thumbs are wrapped in gauze for protection and rest on the occlusive surfaces of the molars while downward and backward pressure is steadily applied until the condyle slides back into the articular eminence. Reduction may require some time and force to overcome muscle spasm; sedation is often required to achieve reduction. Following reduction, instruct the patient to avoid excessively wide mouth opening while eating and yawning for 3 to 4 weeks. Warm compresses to the TMJ, a soft diet for 1 week, and the use of nonsteroidal anti-inflammatory drugs (NSAIDs) are advised. Dental/oral surgery follow-up should be arranged.
TMJ dysfunction secondary to a neuroleptic or antipsychotic medication–related dystonic reaction is treated with diphenhydramine or benztropine.
When trauma is the cause of TMJ dislocation, maintain a high index of suspicion for mandible fractures and cervical spine injuries.
A reportedly successful technique for reduction of TMJ dislocation without sedation involves placing a 5- or 10-mL syringe between the posterior molars and having the patient roll the syringe back and forth while gently biting down until reduction is achieved.
Bilateral TMJ Dislocation Panorex. This Panorex image demonstrates bilateral anterior displacement of the mandibular condyles. (Photo contributor: Jake Block, MD.)