A woman with lock jaw placing her hand on her painful side

Jaw Locking, Causes, Symptoms & Prevention

I feel severe pain on my jaw and ear, I barely can open my mouth. Does this mean my jaw is Locked? What causes jaw locking? Is this a serious problem? What kind of specialist I need to see for jaw lock?

At our Los Angeles dental office, Dr. Khalifeh, a TMJ and Orofacial Pain specialist have treated patients with TMJ and jaw problems on regular basis. If you or some one you know are not able to open your mouth to a normal range or your mouth is open locked, contact us for immediate help.

What is Lock Jaw (Jaw Locking, Locked Jaw)?

It is when you cannot open your mouth to a normal limit. Normally, an adult human can open the mouth 40mm – 55mm. Generally speaking, men can open their mouth more than women. People with flexible joints may open as wide as 65mm. On the other hand, some people might get open jaw lock. While jaw locking mostly happen in one side, it may occur in both sides. 

What are the Types of Jaw Locking (Locked Jaw)?

In general, there are 2 types of jaw lock, open and closed jaw lock. However, some patients have an incomplete frequent open locking that is transient and can be self unblocked. This condition is known as Subluxation.

Open Jaw Lock: 

Is when the mouth is stock wide open and cannot be closed. In this case, the jaw condyle slides out of the joint socket in front of articulating eminence. As mentioned earlier, this problem is more likely to happen in patients with joints hyper mobility conditions such as Ehlers-Danlos Syndrome. However, open jaw lock can also occur in patients with TMJ arthritis. TMJ arthritis may cause changes in the joint bone shape making it easy for the jaw condyle to slide out of the TMJ socket. 

Patients who suffer form open lock for the first time get very scared and nervous. The problem happen when someone open the mouth very wide while yawning or having a big bite. People susceptible to open locking should avoid wide mouth opening. Patients with open jaw locking should seek immediate help. The more they wait, the harder the treatment will be.

X-Ray showing the TMJ condyle position in a patient with open lock jaw

The above x-ray shows the mandibular condyles position in a patient with jaw open lock

Closed Jaw Lock:

Is when someone cannot open the mouth as usual. Jaw locking can be acute or chronic. Acute locking is usually very painful. Patients with closed lock mouth suffer from moderate to severe pain in the TMJ and the jaw muscles. Limited mouth opening may be caused by jaw muscles spasm known as trismus or by TMJ disc disorder

What are the Causes of Jaw Locking (Lock Jaw)?

An open jaw lock is mostly caused by joint hyper mobility such as Ehlers-Danlos syndrome. But it can be caused by TMJ arthritis. However, open lock may happen to any one when trying to force opening the mouth wider than usual.However, the causes of closed jaw lock are:

  • TMJ disc disorder. TMJ clicking is caused by TMJ disc displacement., the disc reduces back to its normal position during mouth opening. If the disc fails to reduce during mouth opening, jaw locking will occur. This problem might happen suddenly while opening the mouth wide for long time such as during long dental visits. However, is may occur while yawing.  Sudden closed locking is usually very painful and requires immediate medical attention by a specialist.
  • Jaw ankylosis. Jaw trauma may cause bleeding in the TMJ. The bleeding inside the jaw joint may cause fibrous or bone adhesion between the joint parts leading to joint ankylosis. Joint ankylosis usually require surgical treatment.
  • Jaw muscles spasm. When the jaw muscles suffer from sustained contraction called Trismus, the jaw might lock.

What are the Causes of Trismus?

  1. Trauma to the jaw and jaw muscle during accidents, fall down, sport injury, jaw surgery, wisdom teeth extractions, etc.. While most muscle related jaw locking will resolve spontaneously with time, some patients might get permanent shortening of the muscles of mastication following muscle injury. However, those patients might need surgical treatment. 
  2. Muscle fatigue which can be caused by opening the mouth for long time or teeth clenching and grinding. However, stress is a major factor in teeth grinding and jaw clenching. 
  3. Infections in the teeth, sinuses, salivary gland, face skin and osteomyelitis, may spread to the jaw muscles. Bacterial or viral Infections involving the jaw muscle and surrounding structures can cause muscle spasm and mouth opening restriction. 
  4. Tetanus disease (Lockjaw), this is a systemic life threatening bacterial infection that causes generalized skeletal muscle spasm. Treatment of Tetanus takes months and require hospitalization. An effective vaccine is available for tetanus which should be taken every 10 years.

Other causes of limited mouth opening include autoimmune conditions such as scleroderma, radiation treatment in the head and neck region and neurological conditions associated with sustained muscle spasm. 

What are the symptoms of mouth locking?

The following are the most common symptoms:

  1. Limited mouth opening (closed locking)
  2. Inability to close the mouth (open locking)
  3. Moderate to severe pain in front of the ear and affected side of the face
  4. Ear fullness
  5. Bite changes

How to avoid Jaw Locking?

Although it might be hard to prevent the mouth locking, there are many things can done to avoid the problem.

  1. Avoid jaw injury, wear sports guard during compact sports.
  2. Do frequent jaw exercises to strengthen your jaw muscles.
  3. Avoid unnecessary wide mouth opening.
  4. Ask your dentist to use short dental visits if you have TMJ disorder.
  5. Ask your dentist to use a bite block during dental treatment if you cannot keep your mouth open for long time.
  6. Use an occlusal splint if you grind or clinch your teeth.
  7. Improve your body posture.
  8. Eat healthy food rich in minerals that helps the muscle stay healthy. Such minerals include magnesium and calcium.
  9. Avoid bad oral habits such as nail biting, ice chewing and excessive gum chewing.
  10. Use stress reduction techniques, stress is a major cause of TMJ disorder

How to Fix Jaw locking (Lock Jaw)?

  • A locked TMJ usually require professional treatment by a specialist. Whether you have an open or a close TMJ locking, the treatment will be focused in reducing your TMJ or the TMJ disc to its normal position. This is done by distracting the joint and placing it in its normal position. TMJ distraction also with be performed to help the non-reducing disc to go back to its normal position.
  • The treatment will involve jaw muscle relaxation and stretching exercises. 
  • Special designed mandibular repositioning splints to help reduce jaw muscles spasm and subsequent TMJ disc reduction. 
  • Patients who waited for long time without seeking help might need to be sedated or placed under general anesthesia to perform the initial treatment.
  • Ankylosed TMJ will require arthroscopic or open joint surgery.

For further assistant, Contact us of call us @: (323) 933-3855.

Scroll to Top