Exodontia.Info
Dislocation of the Mandible /
Jaw Dislocation
Predisposing Factors for Jaw Dislocation:

  • Most dislocations occur spontaneously on opening
    the mouth widely for yawn, dental work, during
    seizure
  • Trauma may also produce dislocation
  • Trauma involving a downward force on partially
    opened jaw
  • Those with previous dislocations are at much greater
    risk for repeat dislocation
  • Shallow mandibular fossa may predispose to
    dislocation
  • Connective tissue diseases like Marfan’s or Ehlers-
    Danlos may have increased risk
  • May eventually result in osteoarthritis in TM joint
Clinical Findings:

  • Dislocations of the lower jaw (mandible) tend to be
  • The presence of a jaw fracture increases the pain
  • Patients are unable to close mouth completely
  • Difficulty speaking and, possibly, swallowing
  • Dislocations may be one-sided or both (unilateral or
    bilateral)
  • The lower jaw comes forward (prognathic)
    appearance to jaw when both are dislocated

Imaging Findings:

  • Conventional X-ray is usually diagnostic
  • Mandibular condyle lies forward (anterior) to the
    articulate eminence on one or both sides
Useful Websites:

Medicsdirect

National Center for Emergency Medicine Informatics

Emedicine.com

LearningRadiology.com

Patient UK


Useful Articles:

Emerg Med J 2008.  Bilateral temporomandibular joint
dislocation following pulmonary function testing. A case
report & review of closed reduction techniques

Dental Update 2009. Bilateral TMJ Dislocation in a
23-month-old Infant - A Case Report

J Oral Maxillofac Surg 2009.  Treatment of Chronic
Mandibular Dislocations. A Comparison Between
Eminectomy and Miniplates
Normally, the mandibular condyle lies in the mandibular
fossa of the temporal bone
when the mouth is closed and
moves forward slightly when the mouth is open.

When dislocated,
mandibular condyle moves forward
and lies forward (
anterior) to the articular eminence
which prevents its return to the
mandibular fossa of the
temporal bone
.
Treatment:

  • Manual reduction is usually performed +/- sedation
    +/- LA
  • Success is evident as patient can close mouth
  • There is a risk of fracture of the lower jaw
    (mandible) during reduction
Last Updated 24th November 2010