Anterior dislocation shifts the lower jaw forward if the mouth excessively opens. This type of dislocation may happen bilaterally or unilaterally after yawning. The muscles that are affected during anterior jaw dislocation are the masseter and temporalis which pull up on the mandible and the lateral pterygoid which relaxes the mandibular condyle. The condyle can get locked in front of the articular eminence. Posterior dislocation is possible for people who get injured by being punched in the chin. This dislocation will push the jaw back affecting the alignment of the mandibular condyle and mastoid. The external auditory canal may be fractured. Superior dislocations occur after being punched below the mandibular ramus as the mouth remains half-open. Since great force occurs in a punch, the angle of the jaw will be forced upward moving towards the condylar head. This can result in a fracture of the glenoid fossa and displacement of the condyle into the middle cranial fossa, potentially injuring the facial and vestibulocochlear nerves and the temporal lobe. Lateral dislocations move the mandibular condyle away from the skull and are likely to happen together with jaw fractures.Posterior, superior and lateral dislocations are uncommon injuries and usually result from high-energy trauma to the chin. By contrast, anterior dislocations are more often the result of low-energy trauma (e.g. tooth extraction) or secondary to a medical condition that affects the stability of the joint (e.g. seizures, ligamentous laxity, degeneration of joint capsule). Diagnosis
As with other joint dislocations, clinical history and examination are crucial for diagnosis of a jaw dislocation.
Commonly, plain and panoramic X-ray radiographies are used to determine the relative position of the mandibular condyle. If a complex or unusual injury is suspected, three-dimensional computed tomography is most reliable in diagnosing dislocation and possibly associated fractures or soft tissue injuries.In case of dislocations resulting from high-energy trauma, attention must also be paid to possible other injuries, particularly blunt or indirect trauma to the skull and cervical spine. Acutely life-threatening conditions need to be ruled out or treated in first line. For superior jaw dislocation in particular, serious intracranial complications such as epidural hematoma are possible and must be recognized and managed to prevent disability or even death. Therefore, neurological status has to be examined in patients with complex dislocations involving temporal bone fractures. Hearing deficits on the injured side may indicate damage to structures of the ear. Treatment
Most temporomandibular disorders (TMDs) are self-limiting and do not get worse. Simple treatment, involving self-care practices, rehabilitation aimed at eliminating muscle spasms, and restoring correct coordination, is all that is required. Nonsteroidal anti-inflammatory analgesics (NSAIDs) should be used on a short-term, regular basis and not on an as needed basis. On the other hand, treatment of chronic TMD can be difficult and the condition is best managed by a team approach; the team consists of a primary care physician, a dentist, a physiotherapist, a psychologist, a pharmacologist, and in small number of cases, a surgeon.