Lockjaw (Jaw Will Not Open Fully)

In plain English

What lockjaw (jaw will not open fully) usually means

Lockjaw is the everyday name for a jaw that will not open fully, which clinicians call trismus. You may notice that a sandwich, a toothbrush or two fingers no longer fit between your front teeth, often with tightness or pain in the cheek or in front of the ear. The cause is usually in the jaw joint, the chewing muscles or the tissue around the back teeth. Stiffness can follow dental work or wisdom tooth removal, a disc inside the joint can slip and block movement, and an injury can limit opening. A spreading dental infection is the cause that makes this a warning sign: a jaw that will not open together with facial swelling, fever or trouble swallowing is a same-day emergency. Call 911 or go to the ER if breathing or swallowing is affected. Lockjaw is also an old name for tetanus, a rare but serious infection. Jaw stiffness and muscle spasms after a wound mean going to the emergency room. Otherwise, see a dentist or doctor the same day or the next day.

Jaw joint and muscle problems

A disc inside the jaw joint can slip forward and block the joint, sometimes after a period of clicking that suddenly stops. Clenching or grinding can also leave the chewing muscles tight and sore. Opening is typically limited and may pull to one side, without fever or swelling.

Stiffness after dental work

Holding the mouth open for a long appointment, or a numbing injection near the back teeth, can leave the muscles sore and tight for a time. This usually shows within a day or two of treatment. Tell the dentist who treated you, especially if it is worsening instead of easing.

Wisdom teeth

Limited opening is common in the days after wisdom tooth removal. It can also come from infection in the gum around a partly erupted wisdom tooth, which typically brings a sore, swollen flap of gum, a bad taste and pain on biting. Increasing stiffness, swelling or fever after surgery warrants a same-day call to the surgeon.

Dental infection spreading toward the jaw

An abscess from a tooth or gum can spread into the spaces around the chewing muscles. Warning features are a painful tooth or gum, swelling of the face or under the jaw, fever, feeling unwell and a mouth that opens less each day. This is a same-day emergency, and trouble swallowing or breathing means 911.

Jaw injury

A blow to the face, a fall or a sports injury can bruise the muscles, damage the joint or break the jawbone. Limited opening after an injury, a bite that feels different, numbness of the lip or chin, or bleeding in the mouth should be assessed at an emergency room or urgent care.

Tetanus

Tetanus is a rare but serious infection that can enter through a cut, puncture or burn, and it is uncommon in people whose vaccinations are up to date. Early signs can include a stiff jaw, muscle spasms and difficulty swallowing in the days or weeks after a wound. This needs the emergency room, not a dental visit.

What a dentist does about it

A dentist or doctor will ask when the stiffness began, whether it followed dental work, an injury or a wound, and whether there has been swelling, fever, a bad taste or trouble swallowing. They typically measure how far the mouth opens, feel the joints and chewing muscles, look at the teeth and gums as far as the opening allows, and check the neck and the floor of the mouth for swelling. X-rays or a scan may be used to look at the teeth, the joint or the jawbone. Treatment follows the cause. An infection is treated at its source, sometimes urgently in a hospital. Joint and muscle causes are usually managed conservatively with rest, a soft diet and follow-up, and sometimes referral to an oral surgeon or another specialist. Any stretching or movement is something a clinician directs once the cause is known.

Until you can be seen

While you arrange to be seen, keep things gentle. Do not force the jaw open, pry it with fingers or objects, or try stretching on your own, since forcing can worsen an injury or an infection. Choose soft or liquid foods that need little chewing, and keep sipping water. Over-the-counter pain relief may be taken as directed on the label after checking with a pharmacist. Avoid putting heat on a swollen face. These steps are comfort only and do not replace being assessed the same day or the next day. Facial swelling, fever or trouble swallowing with a jaw that will not open is a same-day emergency, and trouble breathing means 911.

Note — Timing

When to See a Dentist

Table 1 — Possible causes

Possible Causes of Lockjaw (Jaw Will Not Open Fully)

1. 01Jaw joint or chewing muscle problems, including a slipped joint disc
2. 02Muscle stiffness after dental work, an injection or a long appointment
3. 03Wisdom tooth removal, or infection around a wisdom tooth
4. 04A dental infection or abscess spreading toward the jaw muscles
5. 05A jaw injury or fracture
6. 06Tetanus, a rare but serious infection that can follow a wound

Table 2 — Home remedies & self-care

Home Remedies & Self-Care

These may help manage symptoms temporarily while waiting for professional care.

• 01Do not force the jaw open or try to stretch it yourself
• 02Choose soft or liquid foods that need little chewing
• 03Sip water regularly so you stay hydrated
• 04Over-the-counter pain relief, taken as directed on the package label; ask a pharmacist

Table 3 — Common treatments

Common Treatments for Lockjaw (Jaw Will Not Open Fully)

These dental procedures are commonly used to treat lockjaw (jaw will not open fully).

Table 4 — Common questions

Frequently Asked Questions About Lockjaw (Jaw Will Not Open Fully)