Lockjaw: What Causes It, and How Serious Is It?

Lockjaw is a painful condition that makes it difficult to open or close the mouth. Often associated with tetanus, lockjaw can be caused by many other factors. Luckily, it’s easy to treat.


Lockjaw, a symptom of tetanus, can result from such causes as too much chewing, noshing on tough foods like bagels), TMJ disorder, and jaw pain.

© Katarzyna Bialasiewicz | Dreamstime.com

Have you ever been awakened with searing pain in your mouth or an inability to open your jaw? It’s a scary experience and, according to the National Institute of Dental and Craniofacial research, one that’s not totally uncommon. More than 10 million Americans suffer from a temporomandibular joint disorder (TMD), a symptom of which is lockjaw.

What Is Lockjaw?

This painful medical condition causes swelling, pain, and dysfunction in the temporomandibular joint. The result of this inflammation: Your jaw feels “locked” due to muscle spasms and inflammation, leaving you unable to open or shut normally. Lockjaw typically affects only one side of the jaw. The good news: Lockjaw is relatively harmless and treatable, as long as it isn’t associated with tetanus. Read our sidebar “Lockjaw vs. Tetanus” to learn more about this rare disorder.

Who Gets Lockjaw?

Lockjaw affects almost twice as many women as men. The reason can be blamed on hormones, says Tyrone Rodriguez, DDS, a spokesperson for the American Dental Association (ADA) and a board-certified pediatric dentist in central Washington State. “[The jaw is] a very unique type of joint because it floats, so it’s disconnected at both ends and this joint actually has more estrogen receptors in it,” he explains. “Hormonal changes impact the sensitivity, and some think that it may impact the qualities of the joint when there are changes in hormones.”

In other words, surges and depletions in estrogen caused by things like PMS and menopause can affect pain and swelling—hence the reason it affects more women than men.


The main symptoms of lockjaw include pain and inflammation, which lead to a “locked” jaw that cannot open or close properly. Other symptoms include: pain in the head, face, neck, and shoulders, chronic migraines, teeth grinding, popping sounds in the jaw while chewing, hearing problems, blurred vision, and in some cases, jaw dislocation.

Lockjaw Causes

Multiple factors can be blamed for lockjaw. While tetanus is the most well-known, the following causes are much more common:

  • Bruxism (a.k.a. teeth grinding): Bruxism can alter the bite and shorten teeth. “Depending on the amount of clenching and bruxing that’s going on, you can put stress on the teeth,” says Richard Price, DMD and spokesperson for the ADA. “[It’s like] Jake’s law, which basically says if you hit anything hard enough or long enough with a big enough hammer, it’s going to break.”
  • Misaligned teeth: Think of your mouth as a table, suggests Dr. Rodriguez. If the legs don’t line up properly, your table will rock. If you have a misaligned bite (e.g., your teeth are in the wrong position or your arches don’t line up), your “table” will wobble, he explains. “Your mouth always has the desire to create stability, so your muscles are always trying to constantly adjust.” The result: The muscles become overworked, which will contribute to jaw dysfunction such as lockjaw.
  • Stress: Tension manifests itself in multiple ways. For some, “it might be portrayed with clenching teeth or grinding teeth,” Dr. Price says. “Someone else might be a nail-biter, someone else might have a tick, so it differs from person to person.”

The one thing these bad habits all have in common: They can contribute to pain and swelling of the jaw as well as damage to teeth, which can cause a misaligned bite.


The term lockjaw also can be used to describe tetanus, a serious bacterial infection that causes stiffness in the jaw and neck. It frequently progresses to other parts of the body and can be fatal if left untreated. One of the first symptoms of this disorder is stiffness in the jaw. This condition is serious and requires immediate treatment.

Those who are up to date with their tetanus shots and have symptoms related to a TMJ disorder should rest easy. Their lockjaw is most likely related to a temporomandibular joint (TMJ) disorder, which means it’s treatable and not life-threatening.

Other causes of lockjaw include:

  • Too much chewing (e.g., habitual gum chewing or noshing on tough foods like bagels)
  • Opening the jaw too wide (e.g. while yawning or singing)
  • TMJ Disorder
  • Infection (e.g. tetanus)
  • Arthritis
  • Oral diseases
  • Fevers
  • Fibromyalgia
  • A blunt blow to the head, neck, or face (i.e. from violence or the impact of an air bag deployed during a car accident)

Lockjaw Treatments

The first step in treating lockjaw is to visit your dentist, Dr. Price says. First, your dentist will attempt to determine the cause of lockjaw. For a patient whose bite is misaligned, a dentist likely will alter it by fixing or replacing missing teeth, crowns, or fillings. If the cause is an infection (e.g., tetanus), the patient will require medication (or a vaccine, antitoxin, or tetanus immune globulin in the case of tetanus) to try to treat it. If the jaw is dislocated (which is extremely rare) the dentist may put it back in place.

Other treatments include:

  • Wearing a splint: “If you think of somebody who has hurt their knee, they get a knee brace,” says Drl Rodriguez. “Somebody who’s hurt their TMJ needs to get a kind of splint or a mouth brace to stabilize things and help things slow down.”
  • Medications: Those with more severe symptoms may require medication (e.g., anti-inflammatories) to help reduce inflammation.
  • Manual Therapy: Similar to massage therapy, someone trained in intraoral massage can help relieve the tension and tightness caused by over and underactive muscles, he explains.
  • Botox: “If you have a muscle that’s overworked and spasming, what’s happening is it’s tightening things all over and it’s squeezing things that don’t like to be squeezed,” says Rodriguez. “Botox [will] incapacitate that muscle for a time period. It’s going to paralyze it and as a result, it’s going to provide relief.”

Lockjaw home remedies include:

  • Placing a warm compress over the area
  • Altering the diet to include more soft foods (e.g. applesauce, mashed potatoes, pasta, and soups)
  • TMJ exercises (See our post TMJ Exercises)

As a service to our readers, University Health News offers a vast archive of free digital content. Please note the date published or last update on all articles. No content on this site, regardless of date, should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician.

Tags: , , , , , , , , , , , , , , , , , , , , , , , , , ,

Shandley McMurray

Shandley McMurray has written several of Belvoir’s special health reports on topics including stress & anxiety, coronary artery disease, healthy eyes and pain management. Shandley also has authored numerous articles … Read More

View all posts by Shandley McMurray

Comments Comments Policy

Leave a Reply

You must be logged in to post a comment.

Enter Your Login Credentials
This setting should only be used on your home or work computer.