Definition
Broken jaws are usually the result of trauma directly to the face. Fractures of the lower jaw the MANDIBLE are more common than those to the upper jaw the MAXILLA. Occasionally, usually as a result of a road traffic accident, both may occur together.

Incidence
Broken jaws are rare in childhood when the bones are quite springy and much more common in young adults, especially if they drink beer. Men are affected more than women due to their more dangerous habits such as rugby and drinking.

Causes
Violence, sports and car accidents are the main causes of jaw fractures. Legislation to make the wearing of seat belts compulsory has decreased the amount of upper jaw fractures. Well fitting, professionally made gum shields should be worn for all contact sports and certainly prevent dental damage and are likely to prevent more major fractures.

Signs & Symptoms
Following a blow to the jaw fractures should be suspected if there is obvious deformity, teeth do not meet together as they did before, or sharp bits of bone can be felt in the mouth. Fractures of the lower jaw can be confined to the jaw joint and produce pain on biting with or without a change in the bite. Nerves may be damaged by the fracture leading to a numbness of the upper or lower lip.

Complications of Disorder
Without treatment there is a risk of infection of the fracture site and delayed healing. The bones may heal is the wrong position making it impossible to bring the jaws together is their normal position and causing problems with the bite. Teeth are frequently damaged at the same time as fractures occur and may be lost.
Whenever there are major jaw fractures other injuries should be looked for and ruled out. This is particularly the case for injuries of the neck or CERVICAL SPINE which may occur in up to 10% of major maxillofacial injuries.

Tests
X-rays are essential wherever fractures are suspected, the minimum requirement being two views at right angle to each other to demonstrate the fracture and any displacement (movement) of the bones. For major maxillofacial trauma especially if a head injury is suspected a CT scan is preferable.

Treatment
Not all jaw fractures need surgical treatment. If the fracture site is not moveable and the bones are in the right place then many jaw fractures can be left to heal by themselves. For more unstable jaw fractures surgical treatment is preferred. This is usually carried out under general anaesthetic.

INTERMAXILLARY FIXATION or IMF is wiring of the teeth using one solid jaw to support the fractured jaw by holding the two together. This is usually left in place for around 6 weeks.
The alternative and more popular method is OPEN REDUCTION AND INTERNAL FIXATION. This involves an incision inside the mouth over the fracture site, pulling the bone ends together by wiring the teeth together with temporary IMF and then securing the bones with a small metal plate which is screwed across the fracture site. The jaws are then released allowing the patient to eat a soft diet after the operation. This has the obvious advantage of not having to have your jaws wired together for six weeks.