Exodontia.Info
Prolonged Limitation of Mouth Opening (Trismus)
This can be due to medial pterygoid contracture / spasm.

This spasm may be the result of injury of the medial pterygoid muscle caused by a
needle (repeated injections during Inferior Alveolar Nerve block) or by trauma of
the surgical field especially when difficult lengthy surgical procedures are
performed.  Other causative factors are gross infection, inflammation of the post-
extraction wound, hæmatoma and post-operative œdema.
The management of trismus depends on the cause.  Most cases do not require
any particular therapy.  When acute inflammation or a hæmatoma is the cause of
trismus, hot mouth rinses are recommended initially and then broad-spectrum
antibiotics are administered.

Other supplementary therapeutic measures include:

  • Heat therapy, i.e., hot compresses are placed extra-orally for approximately
    20 min every hour until symptoms subside.
  • Gentle massage of the TMJ area.
  • Administration of painkillers, anti-inflammatory and muscle relaxant (such as
    sedatives) medication.
  • Physiotherapy lasting 3 – 5 min every 3 – 4 hours, which includes movements
    of opening and closing the mouth, as well as lateral movements, aimed at
    increasing the extent of mouth opening.
  • Administration of sedatives for management of stress which worsens while
    trismus persists, leading to an increase of muscle spasm in the area
Photos showing a patient with
Trismus and the Use of
Spatulas to Ameliorate the
Trismus
Last Updated 30th December 2011
Useful Articles:

Dental Update 2002. Trismus - Aetiology, Differential Diagnosis and Treatment.

JOMS 2005.  Limited Painful Mouth Opening

British Journal of Oral & Maxillofacial Surgery 2010.  Technical note.  Battling
trismus - the “Pat-Bite” device.

BJOMS 2011.  Reliability & validity of a new method of nurse-led assessment of
trismus
Photos showing a patient with
Trismus and the Use of
Spatulas to Ameliorate the
Trismus
Photo showing a patient with Trismus using a Trismus Screw.  These have to be
used with caution as they can severely traumatised the 'front' teeth and may lead
to their avulsion.