At its most basic if a bone is broken but not pushed out of place by the force of the injury (undisplaced) it will heal as long as it is left undisturbed and force is not put on it. This is the basis of splinting. If it is displaced then it must be put back into the correct position and kept there undisturbed for however long it takes to heal. If it is exposed to the outside world it is at risk of becoming infected and should be returned to normal as soon as possible. If it is multiple pieces the same process has to be followed for healing to happen but it might be very much more complicated.
In the face and skull most bones will heal in around 3 weeks. That means if the bones are not returned to their correct position within that time they will heal and get stuck in the abnormal position. That is called a malunion. To avoid malunion, reduction and fixation are necessary, which may be open or closed (i.e. cuts are made in the mouth or on the skin to get to the fractures and return them to the previous correct position; “reduction” can be done under direct vision or by feel). Using endoscopes counts as a minimal access open reduction. Fixation may be direct with plates and screws (very common), wires (now rare) or indirect fixation (by wiring teeth together in the position that is normal for you. Figure 1 summarizes the procedure: Figure 1, top left, shows a mandible before injury; Figure 1, top right, shows the fractures and misaligned mandible; Figure 1, bottom left, shows the broken mandible after reduction; Figure 1, bottom right, shows the broken and re-aligned mandible after fixation (with plates and screws). This treatment is usually performed under general anaesthesia.
Next section: Broken bone