In short. Jaw fracture repair explained: how mandibular fractures are assessed, when fixation is needed, how the bite is restored, and the honest risks including permanent numbness.
Key points
- The teeth tell the surgeon where the bone belongs.
- In theatre the bite is restored first, often with temporary fixation, and the plates are positioned to hold the fragments in that relationship.
- A jaw that is mechanically solid but meets in the wrong place is a failed operation.
The lower jaw is a ring of bone carrying the only movable joint in the skull, so a fracture anywhere along it disturbs the way the teeth meet. That is the principle governing the whole subject: a broken jaw is treated to restore the bite, not simply to join bone to bone. Fractures occur most often at the angle and at the chin, and two fractures on opposite sides are common in a single injury.
How it is assessed
The clinical assessment checks the bite first: how the upper and lower teeth meet is compared with how they met before, and a change is the most reliable sign that the bone has moved. The surgeon also looks for a step in the line of the teeth, bleeding from the gum line, altered sensation of the lower lip and chin — the nerve runs inside the bone and is often bruised — and restricted or deviated opening. A CT scan defines the fracture lines and their displacement, and a panoramic radiograph shows the relationship between the fracture and the tooth roots.
When fixation is needed
A crack with no displacement and a stable bite may be managed without surgery, with a soft diet and careful review. Most displaced fractures do need surgery, because the muscles attached to the jaw pull the fragments apart and the bite cannot be trusted to heal in position by itself. A fracture near a tooth may require that tooth to be assessed, and any infection needs treatment at the same time.
The bite is the blueprint
The teeth tell the surgeon where the bone belongs. In theatre the bite is restored first, often with temporary fixation, and the plates are positioned to hold the fragments in that relationship. A jaw that is mechanically solid but meets in the wrong place is a failed operation.
How the repair is done
The fracture is exposed through a cut inside the mouth, or a small incision in the skin crease below the jaw edge when a better angle is needed. The fragments are returned to the correct relationship and held with small titanium plates and screws. In some patterns the fixation is placed with an endoscope, which keeps the scars minimal. A few cases can be treated by wiring the teeth together without implants, but this is used less often now because it does not let the jaw function during healing.
Recovery and honest risks
Swelling peaks in the first days and settles over weeks. A soft diet is needed for several weeks, and the plates usually remain in place permanently unless they cause problems. Numbness of the lower lip and chin is common after fracture and after surgery; most of it improves over months, but a permanent patch is a real possibility. Infection, loosening of hardware, delayed union, a bite that does not meet correctly and the need for a further operation all occur; smoking increases each risk.
Seek urgent assessment if
- The teeth no longer meet as they did, or the jaw moves to one side when you open your mouth.
- The lip and chin feel numb, or bleeding comes from around a tooth after an injury.
- You cannot open the mouth more than a finger’s width, or the pain is increasing in the days after an injury.
Frequently asked questions
Why is a broken jaw treated to restore the bite rather than simply to join bone?
Because the lower jaw carries the only movable joint in the skull, so a fracture anywhere along it disturbs the way the teeth meet. In theatre the bite is restored first, often with temporary fixation, and the plates hold the fragments in that relationship. A jaw that is solid but meets in the wrong place is a failed operation.
Do all jaw fractures need surgery?
No. A crack with no displacement and a stable bite may be managed without surgery, with a soft diet and careful review. Most displaced fractures do need surgery, because the muscles attached to the jaw pull the fragments apart and the bite cannot be trusted to heal in position by itself.
Will the numbness in my lip and chin after a jaw fracture go away?
It usually improves over months, but a permanent patch is a real possibility, because the nerve runs inside the bone and is often bruised by the injury as well as by the surgery. Infection, loosening of hardware, delayed union and a bite that does not meet correctly all occur, and smoking increases each risk.
Risks & Limitations
- Reconstruction is usually staged — more than one operation is normal, and the plan may change as healing progresses.
- Donor-site scarring and discomfort, including after rib cartilage harvest.
- Partial or complete failure of a flap or graft, which may require further surgery.
- Scars are permanent. They mature and fade but never disappear.
- Asymmetry and the inherent limits of matching a normal side.
- Altered sensation, numbness or weakness in the operated area.
- Contracture, which may need release procedures later.
- Final assessment is made at 6–12 months, and longer in growing children.
When to Seek Care
- A flap or graft that turns dark, cold, black or stops bleeding when pricked.
- Fever above 38 °C, or spreading redness, warmth or discharge around a wound.
- New or worsening pain, swelling or fluid leakage from the operative site.
- Bleeding that does not stop with gentle pressure.
- Any change in a reconstructed area that concerns you, however minor.
References & Further Reading
- American Society of Plastic Surgeons (ASPS) — reconstructive surgery guidance
- World Health Organization (WHO) — burn and trauma care resources
- Chinese Medical Association, Plastic Surgery Branch — clinical guidance
- Cochrane Library — systematic reviews in wound and reconstructive care
This page is patient education, not medical advice, and it does not cite individual studies. Discuss your own case with a qualified clinician. To arrange an assessment at Chongqing West District Hospital, see Contact & Consultation.