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TEMPOROMANDIBULAR
DISLOCATION
BY DR. MANISHA MISHRA
TMJ
• The temporomandibular joint (TMJ) is the
articulation of the temporal and mandibular bones
• TMJ dislocation occurs when the condyle travels
anteriorly along the articular eminence and
becomes locked in the anterior superior aspect of
the eminence, preventing closure of the mouth.
• This results in stretching of the ligaments, and is
associated with severe spasm of the muscles that
open and close the mouth (ie, the masseter,
internal pterygoid, and temporalis) .
• The resultant trismus prevents the condyle from
returning to the mandibular fossa
Causes:
• Deep yawning
• Prolong Dental procedures
• Airway manipulation particularly in an
anaesthetised patient.
• Dislocation can occur during laryngoscopy,
transoral fiberoptic bronchoscopy and
intubation.
Clinical features:
• TMJ dislocation may occur with trauma, but most
often follows extreme opening of the mouth
during yawning, laughing, singing, vomiting, or
dental treatment .
• Dislocation also can result from dystonic
reactions to drugs .
• Symmetric mandibular dislocation is most
common, but unilateral dislocation with the jaw
deviating to the opposite side also can occur.
• TMJ dislocation is painful and frightening for the
patient.
On examination:
• The patient is unable to close the mouth and there is
excessive salivation .
• A depression may be noted in the preauricular area.
• Palpation of the TMJ reveals one or both of the condyles
trapped in front of the articular eminence and spasm of the
muscles of mastication.
• Patients prone to mandibular dislocation include those
with an anatomic mismatch between the fossae and
articular eminence, weakness of the capsule and the
temporomandibular ligaments, and torn ligaments.
• Patients who have had one episode of dislocation are
predisposed to recurrence .
Diagnosis:
• The dentist bases the diagnosis on the position
of the jaw and the person's inability to close his
or her mouth.
• Radiographs of the TMJ are not always
necessary, but should be obtained to exclude
condylar fracture if the dislocation is related to
trauma
• The problem remains until the joint is moved
back into place. However, the area can be tender
for a few days.
Treatment :
• The muscles surrounding the temporomandibular joint
need to relax so that the condyle can return to its normal
position.
• Many people can have their dislocated jaw corrected
without local anesthetics or muscled relaxants. However,
some people need an injection of local anesthesia in the
jaw joint, followed by a muscle relaxant to relax the
spasms.
• The muscle relaxant is given intravenously (into a vein in
the arm). Rarely, someone may need a general anesthetic
in the operating room to have the dislocation corrected.
• In this case, it may be necessary to wire the jaws shut or
use elastics between the top and bottom teeth to limit the
movement of the jaw.
• To move the condyle back into the correct position,
a doctor or dentist will pull the lower jaw downward
and tip the chin upward to free the condyle .
• The doctor or dentist then guides the ball back into
the socket.
• After the joint is relocated, a soft or liquid diet is
recommended for several days to minimize jaw
movement and stress.
• People should avoid foods that are hard to chew,
such as tough meats, carrots, hard candies or ice
cubes, and advice not to open their mouths too
widely.
Prevention:
 TMJ dislocation can continue to happen in people with
loose TMJ ligaments. To keep this from happening too
often, dentists recommend that people limit the range of
motion of their jaws, for example by placing their fist
under their chin when they yawn to keep from opening
their mouths too widely.
 Conservative surgical treatments can help to prevent the
problem from returning.
 Some people have their jaws are wired shut for a period
of time, which causes the ligaments to become less
flexible and restricts their movement.
 In certain cases, surgery may be necessary.
 Eminectomy removal of the articular eminence so that
the ball of the joint no longer gets stuck in front of it.
 Another procedure involves injecting medications into
the TMJ ligaments to tighten them.
Prognosis:
• The outlook is excellent for returning the
dislocated ball of the joint to the socket.
• However, in some people, the joint may continue
to become dislocated , If this happens, needs
surgery.