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


  • Most dislocations occur spontaneously on opening the mouth widely for yawn, dental work, during an epileptic
    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 uncomfortable but not severely painful for the patient
  • 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 (pro-gnathic) appearance to jaw when both are dislocated
Useful Websites:


Canadian Dental Association

Drugs.com

Emedicine.com

Medscape

Merck Manual


Useful Articles:

Ind J Anaesth 2004.  Temporomandibular Joint (TMJ) Dislocation During LMA Insertion

J Craniofacial Surg 2008.  A Clinical Study on Treatment of Temporomandibular Joint Chronic Recurrent
Dislocations by a Modified Eminoplasty Technique

Pakistan Oral & Dent J 2008.  Treatment of TMJ Recurrent Dislocation through Eminectomy - A Study

Anesth Prog 2009.  Use of Masseteric & Deep Temporal Nerve Blocks for Reduction of Mandibular Dislocation

Annals Plastic Surgery 2009.  Temporomandibular Joint Dislocation Reduction Technique.  A New External Method
vs. the Traditional

BJOMS 2009.  Long-Term Efficacy of Botulinum Toxin Type A for the Treatment of Habitual Dislocation of the TMJ

JOMS 2009.  Autologous Blood Injection for the Treatment of Chronic Recurrent TMJ Dislocation

Head & Face Medicine 2011.  Evaluation of the Mechanism & Principles of Management of TMJ Dislocation.  
Systematic Review of Literature & a Proposed New Classification of TMJ

BJOMS 2012.  Technical Note.  Intra-Oral High Condylotomy for a Case of Chronic Mandibular Dislocation

Ann Dent Specialty 2014.  Case Report.  Autologous Blood Injection for Treatment of Recurrent TMJ Dislocation

Patient.co.uk 2014.  Mandibular Dislocation
Reduction:

Once radiographs have been obtained that confirm a
dislocation and exclude a mandibular fracture, reduction
attempts may proceed. Patients with
mandibular fractures should be referred to the OMFS Department.  
Uncomplicated
dislocations can be managed in the A&E ± LA ± conscious sedation.

If the
dislocation has just happened, no sedation or LA is needed.  The longer the patient has been dislocated, the
more likely either LA ± sedation or in more severe cases, GA.

Relocation:

An initial attempt can be made for the patient to self-relocate by eliciting the
gag-reflex.  Stimulation of the soft
palate can induce the patient to gag.  This can spontaneously re-locate the
subluxed mandible.

Gauze pads should be wrapped around both thumbs to prevent human bite injuries as the
mandible is reduced. The
thumbs are placed on the lower molars (or over the
retro-molar pads) and the inferior surface of the mandible is
grasped with the fingers on each side. Downward pressure is exerted on the lower molars to free the
condyle from
its entrapped position in front of the
articular eminence.

Following this, the
mandible is eased backwards to return it to its anatomic position. Successful reduction is usually
evident as the teeth will close rapidly due to
masseter spasm and a palpable (and sometimes audible) clunk occurs
on reduction. The clinician must beware of having their thumbs being trapped in an inadvertent human bite as the
mandible relocates.
Dislocation of the mandible / jaw dislocation / TMJ subluxation is an infrequent A&E presentation.

The condition is discomforting to the patient, although most are not in severe pain.  In the majority of cases, the
mandible (lower jaw) can be reduced by the A&E staff using simple techniques.  Rarely, a mandibular dislocation
may require open reduction under general anæsthesia.

Once the
condyle (see below diagram) comes out of its fossa, it comes to lie in front of the articular eminence and
is mechanically blocked from spontaneously moving back into its correct position (in the
fossa).

Spasm of the
masseter and pterygoid muscles (chewing muscles) results in trismus (limited mouth opening) and
further traps the
condyle in its dislocated position.  The resulting dislocation may be one sided or both. In either
case, the patient will be unable to completely close the mouth and will often have difficulty speaking.

The
dislocation is surprisingly not very painful unless an associated mandibular fracture is present.
Imaging Findings:

  • Conventional X-ray is usually diagnostic
  • Mandibular condyle lies forward (anterior) to the articulate eminence on one or both sides
Barton Bandage to reduce the chance of further TMJ Subluxation
Follow-Up:


Further Inpatient Care:

In the rare cases of mandible dislocation that cannot be reduced by the method described above, attempted closed
reduction under GA or open reduction may be required. Similarly, chronic
dislocations or fractures / dislocations of
the
mandible are best reduced by OMFS or ENT specialists.

Further Outpatient Care:

Successfully relocated
mandibular dislocations do not require any specific ongoing treatment, although the patient
should be cautioned against wide opening of the mouth, which could easily cause a recurrence.

All patients with reduced
mandibular dislocations should be followed-up by an appropriate specialist because of the
possibility of jaw instability,
ligamentous damage and chronic TMJ pain.


Complications:

Serious complications from
mandibular dislocation are rare.  There are several complications that are associated
with the
dislocation and reduction.

Dislocation complications:

Fracture of the
mandibular condyle can occur during dislocation. Open fractures are at risk for infection and
osteomyelitis. Interposition of soft tissues may make the dislocation irreducible.

Injury to the
external carotid artery and facial nerve have been reported.

Complications of Reduction:

The clinician accomplishing the reduction may sustain a human bite as the jaw closes rapidly on reduction.

The
mandibular condyle may fracture as it passes under the articular eminence.

Prognosis:

Because the
dislocation occurs in anatomically predisposed individuals and disrupts the joint capsule and ligaments
that stabilise the TMJ, recurrent
dislocation is very common.

Recurrent
dislocation often results in osteo-arthritis of the TMJ with chronic pain and inflammation.

There are many surgical interventions to correct chronic
dislocation and painful TMJ syndrome that are described
in the ENT literature. Because so many of the patients with
mandible dislocation experience recurrent dislocation, it
is advisable to refer all of these patients to an appropriate specialist for follow-up.

Patient Education:

Patients should be instructed to avoid opening their mouths widely to prevent recurrent
dislocation.
Confirmation of relocation:

Repeat radiographs are indicated to confirm reduction and exclude the possibility of fracture during reduction.

The patient should be observed for
airway patency and if sedation has been used, vital signs monitored until the
effects of the sedatives have worn off.

The patient should be cautioned to avoid wide opening of the mouth to prevent recurrent
dislocation. A Barton's
bandage
is applied to prevent wide mouth opening and recurrent dislocation.
Relocation of the subluxed TMJ - note, gauze wrapped around
the thumbs
Last Updated 13th February 2020