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What is Trismus?

A man holding his hand to his cheek

Trismus otherwise known as “lock jaw” can be very painful and uncomfortable. After a dental procedure an individual may experience an extended period of discomfort and pain. The symptoms may restrict an individual’s ability to eat, drink, and speak properly leading to other health complications. Left untreated this may only get worse. An Expert may offer at-home treatments until one is able to see their dentist. A consultation with a dentist may find the underlying cause and offer a treatment plan to relieve the discomfort and pain.

Trismus Definition

Trismus is a muscle spasm, which may be due to over-use of the muscles due to clenching or grinding of the teeth, or due to an infection in the vicinity of the jaw muscle.  This may be used to describe restrictions caused by trauma, surgery or radiation. The ability to open the mouth could be limited and may create serious health implications. 

Trismus brought on by micro-trauma due to bruxism could create limitations of the jaw movement. Self generated causes, may include third molar extraction, hematomas resulting from a dental injection and late effects of intermaxillary fixation after a mandible fracture or other trauma.

Trismus Treatment

  • Heat Therapy. The application of moist compresses for 15-20 minutes/hour 4 times each day for several days until the symptoms have relieved. 
  • Warm saline rinses. A teaspoonful of salt added to a glass of water. Holding the liquid mixture in the mouth on the affected side for a few minutes then spit it out. 
  • Medication: Muscle relaxants as prescribed by your dentist. 
  • Physiotherapy should also be done which includes mouth opening exercises, as well as, lateral excursions (side to side movements), for 5 to 10 minutes every 3 to 4 hours. 

What to do if one’s jaw locks in place and cannot release?

Try moist heat application, gentle stretching exercises, and/or a muscle relaxant medication to relieve the pain. To reduce a jaw clenching habit, bruxism, might require the use of a night guard.; If it's the result of a dental infection, extraction or root canal therapy may be required.

How long does pain and jaw limitations last after undergoing a Novocain injection?

If caused by the injection, it could take up to two weeks for the pain to subside. The injection may have penetrated into the muscle causing these symptoms. Apply a warm wet cloth to the jaw along with exercise and, if needed, a muscle relaxant for relief.

Will a wisdom tooth extraction cause jaw pain and tension?

Trismus, or locked jaw, is a common complication following the extraction. This could be caused by a direct or indirect trauma to the muscles caused by the injection itself or by the effects of the local anesthetic solution. Exercise may relieve the pain until you can your dentist.

Can a deep dental cleaning cause lock jaw?

When the mouth is kept open for a long period of time, this may create muscle spasms and a shortening of the jaw muscles resulting in trismus, “lock jaw.” 

Limited jaw mobility can result from trauma, surgery, radiation treatment or even problems associated with TMJ. The limitations in trismus may be a result of muscle damage, joint damage, rapid growth of connective tissue or a combination. Of the various causes, dental is the most common. This may also be associated with a muscle tetany from the onset of a neurological or neuromuscular disease or a severe electrolyte imbalance due to dehydration or kidney disorder. For more information about treatment contact Experts on JustAnswer for real time answers.


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