Open Wound of the Jaw

First aid for a jaw wound

1. Stop the bleeding. Press firmly with a clean cloth or gauze for 10 minutes without lifting to check. Face and jaw wounds bleed heavily but usually stop with pressure.
2. Check for other injuries. Look for broken teeth, an altered bite, difficulty opening the mouth or signs of head or neck injury. If a neck injury is possible, keep the head still and call 911 or your local emergency number.
3. Clean it. Once bleeding slows, rinse with clean running water for several minutes. Remove loose dirt, but leave embedded objects for a clinician.
4. Cover it with a clean dressing.
5. Save any knocked-out tooth by holding it by the crown, rinsing briefly and placing it in milk or back in the socket, then see a dentist immediately.
6. Apply a cold pack wrapped in cloth for 10 to 15 minutes to reduce swelling.

Why jaw wounds need careful assessment

The lower jaw (mandible) is the most commonly fractured facial bone after the nose. A blow hard enough to split the chin can also fracture the jaw, often at the opposite side or at the joints in front of the ears. Nearby structures can be damaged:

• The facial nerve branch that moves the lower lip runs along the jawline. Injury causes a lopsided smile.
• The inferior alveolar and mental nerves supply feeling to the lower lip and chin. Numbness here often signals a jaw fracture.
• The parotid and submandibular glands and their ducts sit near the jaw angle and under the jaw.
• Teeth can be cracked, loosened or pushed into the wound. See dental trauma.

A wound that passes through into the mouth (a through-and-through laceration) is common after falls onto the chin. It needs closure in layers and carries a higher infection risk.

Diagnosis

The clinician will ask how the injury happened and examine the wound under good light, often after numbing it. They test the bite, jaw opening, sensation of the lip and chin, facial movement and the teeth. Imaging is used if a fracture or foreign body is suspected:

• Panoramic dental X-ray for the lower jaw
• CT scan for complex facial injuries or suspected fracture of the jaw joints
• X-ray or ultrasound to look for glass, gravel or tooth fragments in the wound

Treatment

Closing the wound

• Tissue glue or adhesive strips for small, straight, low-tension cuts.
• Fine stitches for most chin and jaw wounds. Deeper layers may need dissolvable stitches beneath the skin.
• Stitches inside the mouth are usually dissolvable and fall out within 1 to 2 weeks.
• Lip border repairs need precise alignment of the vermilion line to avoid a visible step.
• Specialist repair by a plastic or oral and maxillofacial surgeon for nerve or duct injuries, tissue loss, complex wounds or fractures.

Most face wounds can be closed safely up to about 24 hours after injury because of the good blood supply, but sooner is better.

Preventing infection

• A tetanus booster if your last dose was more than 5 years ago for a dirty wound, or 10 years for a clean one.
• Antibiotics for animal or human bites, wounds into the mouth, heavily contaminated wounds and open fractures.
• Rinsing with salt water after meals for wounds inside the mouth.

Treating a fractured jaw

Fractures may be treated with a soft diet if stable, or with surgery using small plates and screws, or by wiring the teeth together for a few weeks.

Aftercare and healing

• Keep the wound clean and dry for 24 to 48 hours, then wash gently twice a day.
• Apply petroleum jelly to keep the wound moist.
• Eat soft foods and avoid stretching the mouth wide while it heals.
• Facial stitches are removed after about 5 to 7 days.
• Watch for infection: spreading redness, warmth, pus or fever. See infection of an open wound.
• Protect the scar from the sun with SPF 30 or higher for at least 6 to 12 months to prevent darkening.
• Massage the scar gently once it is healed. Silicone gel or sheets can flatten raised scars.

Complications

• Wound infection
• Widened, raised or keloid scars
• Permanent numbness or weakness if nerves were damaged
• Salivary fistula or swelling (sialocele) after gland or duct injury
• Malocclusion (teeth not meeting properly) after a missed fracture

Frequently asked questions

Does a cut on the jaw need stitches?

It usually does if it gapes, is longer than about 1/2 inch (1 cm), is deep, goes into the mouth or crosses the lip border. Small, shallow cuts whose edges stay together can be closed with glue or strips. Have it assessed within a few hours for the best scar.

How long does a jaw wound take to heal?

The skin seals within about a week, and facial stitches come out in 5 to 7 days. The wound regains most of its strength over 6 to 8 weeks, and the scar continues to flatten and fade for 6 to 12 months.

How do I know if my jaw is broken as well?

Signs of a broken jaw include teeth that no longer fit together, pain or difficulty opening and closing, numbness of the lower lip or chin, swelling, and bleeding from the gums. A doctor will check with an X-ray or CT scan.

Will a chin laceration leave a scar?

Most leave some scar, but careful repair, keeping the wound moist, avoiding sun exposure and scar massage make it much less visible. Scars under the chin are often hidden. If a scar stays raised or tight after several months, treatments such as silicone, steroid injections or revision surgery can help.