Lockjaw: Symptoms, Causes & Treatment

Lockjaw is a prolonged contraction of the jaw muscles that makes it hard or even impossible to open the mouth. It can be caused by procedures such as wisdom tooth removal or by conditions such as tetanus, and it can also be a side effect of head and neck cancer treatment.

Depending on the cause, lockjaw may occur with other symptoms. These can include jaw muscle spasms and pain when talking, eating, or yawning.

If you have lockjaw, you should see your primary care provider or a dentist for diagnosis and proper treatment. Treatment may include anti-inflammatory medications, muscle relaxants, physical therapy, and, in some cases, surgery.

Main symptoms

The main symptoms of lockjaw are:

• Difficulty and pain when opening the mouth

• Jaw muscle spasms

• Pain when talking, eating, or moving the jaw

• Pain when yawning

Symptoms of lockjaw vary depending on the cause. They may also include gum pain and swelling, fever, weight loss, voice changes, and involuntary muscle contractions in the hands and feet.

What causes lockjaw?

Possible causes of lockjaw include:

1. Temporomandibular disorder

Temporomandibular disorder (TMD) is a problem affecting the temporomandibular joint (TMJ) and the chewing muscles.

According to the National Institute of Dental and Craniofacial Research, TMDs can cause pain and dysfunction in the jaw joint and the muscles that control jaw movement, leading to symptoms such as jaw and facial pain, jaw stiffness, and pain when chewing or talking.

2. Wisdom tooth removal

Lockjaw, pain, and swelling are complications that can happen after wisdom tooth extraction or removal. These complications occur due to inflammation caused by the procedure and usually do not last long.

3. Tooth infections

Severe tooth infections, such as pericoronitis and abscesses, can affect the chewing muscles. This can lead to lockjaw and other symptoms, such as swelling and pain in the area, sensitivity to hot or cold foods or drinks, bad breath, fever, and a bad taste in the mouth.

4. Head and neck cancer treatment

Lockjaw is a common side effect of head and neck cancer treatment because radiation therapy can cause fibrosis to form in the chewing muscles.

In addition, surgeries to treat head and neck cancer can also lead to scar tissue in the muscles of the temporomandibular joint and limit mouth opening.

5. Tetanus

Tetanus is an infection caused by the bacterium Clostridium tetani and, according to the CDC, can cause jaw cramping, sudden involuntary muscle spasms, and painful muscle stiffness, which can lead to lockjaw.

6. Rheumatoid arthritis

Rheumatoid arthritis can cause lockjaw because it affects muscles and joints throughout the body. It can also affect the jaw, causing limited jaw movement, pain, swelling, and difficulty chewing.

7. Complications from anesthesia

Anesthesia can sometimes unintentionally affect the chewing muscles by blocking a nearby nerve that supplies the lower front and back teeth. This can lead to temporary lockjaw because of pain when trying to move the jaw.

Anesthesia can also cause lockjaw as a result of injury to an artery or nerve, which may lead to bruising and infections.

8. Trauma

Lockjaw can occur due to trauma to the face or jaw. This may be caused by surgery, car accidents, violence, or sports injuries, for example.

Confirming a diagnosis

Lockjaw is diagnosed by a primary care provider or dentist through an assessment of symptoms and an examination of the jaw and neck.

To confirm the diagnosis, the provider may also order imaging tests, such as a CT scan or MRI.

Treatment options

Treatment for lockjaw depends on the underlying cause and may include:

• Medications, such as muscle relaxants like diazepam, anti-inflammatory drugs, antibiotics, and pain relievers like aspirin

• Warm compresses, using warm, moist towels for 15 to 20 minutes every hour, which can help relax the muscles and reduce muscle spasms

• Stretching exercises, such as opening and closing the mouth and moving the jaw from side to side for 5 minutes every 3 to 4 hours, which may be recommended for people with lockjaw caused by trauma or surgery

• Physical therapy, to reduce swelling, restore blood flow, and improve range of motion and muscle strength, which may be recommended in cases of fibrosis or radiation therapy, for example

Surgery may be recommended if lockjaw does not improve after 2 to 3 days of treatment or in cases of severe lockjaw. Surgical options can include reducing jaw height, coronoidectomy, or releasing tight tissue, sometimes with free flap reconstruction.

Is lockjaw serious?

Temporary lockjaw is not usually serious, but it can interfere with speech, eating, chewing, and swallowing.

When it lasts a long time, lockjaw can lead to fibrosis in the TMJ, which is the joint formed by the jawbone and other joint structures. This can limit mouth opening and cause difficulty chewing, speaking, and maintaining oral hygiene.

How long does it last?

Lockjaw usually lasts about two weeks, depending on its cause and the treatment recommended by the doctor.

However, in some cases, such as fibrosis caused by radiation therapy, lockjaw may last longer and be more resistant to treatment.