Fracture Fixation: IMF, Miniplates and Arch Bars Explained

Once a broken jaw or midface bone is pushed back into place, it must be held perfectly still while new bone grows across the break — that is fixation. In the face, fixation is special because the teeth act as a built-in splint: surgeons anchor broken bone to the teeth, or fix bone directly with tiny metal plates, always using the bite as the guide.

The three workhorses are intermaxillary fixation (IMF — wiring upper and lower teeth together), titanium miniplates with screws, and arch bars (metal bars wired around the teeth as anchors). The choice decides how long a patient sips liquids versus how soon they chew soft food.

Key Concepts

• IMF: upper and lower teeth linked with wires or elastics so the jaws cannot open; holds fractures 4-6 weeks using the bite as the splint.
• Miniplate osteosynthesis: small titanium plates (usually the 2.0 mm system) screwed across the break; rigid enough that IMF is often unnecessary.
• Arch bar: a malleable bar wired to the teeth, giving wires and elastics something to grip — the classic IMF anchor.
• Occlusion: how upper and lower teeth meet; restoring the pre-injury bite is the goal of all fixation.
• Rigid vs semi-rigid: plates fully immobilising the break versus techniques allowing tiny movement; each suits different fractures.

How It Works

1. Record the bite first. Note the pre-injury bite from models, photos or memory — that is the target.
2. Apply the arch bar. Adapt the bar along the teeth and secure it with 26-gauge wires twisted around each tooth's neck.
3. Reduce and wire. Manipulate fragments until the bite is right, then link upper and lower bars — the jaws are fixed shut.
4. Or plate directly. Expose the fracture, clamp the pieces, and place a miniplate with at least 2 screws each side of the break.
5. Aftercare. IMF patients get liquids, emergency wire cutters and strict hygiene; plated patients start gentle movement within days.

Worked Example

A lower-jaw fracture gets an Erich arch bar secured with one wire around each of 14 teeth — 14 wires, about 30-40 minutes of chair time. IMF lasts 5 weeks (35 days) on roughly 1,800 ml of liquid diet daily. The same fracture with two 4-hole miniplates uses 2 × 4 = 8 screws; IMF is needed only during the 2-hour operation, and a soft diet starts on day 3 — saving roughly 32 wired-shut days compared with IMF alone.

Common Misconceptions

• "Wiring the jaw shut is obsolete." IMF remains standard for condylar fractures, children's fractures and during plating surgery.
• "Titanium plates must come out later." Titanium is biocompatible and usually stays for life; removal is only for infection or exposure.
• "Normal eating resumes when wires come off." Bone needs the full 6 weeks; early hard chewing can re-break it.

Real-World Applications

• Maxillofacial trauma surgery: every jaw fracture uses one or a combination of these methods.
• Orthognathic surgery: miniplates holding repositioned jaws after planned cuts.
• Field stabilisation of jaw injuries in military and sports medicine.

IMF, miniplates and arch bars are three tools for one job — holding broken facial bones still until they heal, with the bite as the guide. Wiring is simple and reliable, plating frees the patient faster, and arch bars anchor both.