Mandible Fractures at North Austin Campus

The mandible (man-duh-bul) is the lower jaw. Young children have 10 deciduous teeth (baby teeth) in the mandible. Adults have 16 permanent teeth (adult teeth) in the mandible. When a mandible is fractured, the goals of treatment are to allow healing, and to restore the bite pattern to what it was before the injury.

The parts of the mandible include the condyle, the coronoid, the ramus, the body, the parasymphysis and the symphysis (Figure 1). Any of these may be fractured. Sometimes, two or more fractures may be present.

Figure 1: Parts of the mandible

Fractures of the mandible that have not moved, and where the bite has not changed (non-displaced fractures) may be treated with soft diet, rest and close observation for 6 weeks. However, in many mandible fractures, there is some degree of displacement and change in the bite pattern. In those cases, surgery may be needed.

Surgical treatment for mandible fractures in children must take into account the buds of the adult teeth (which are inside the bone), and the future growth of the mandible. Regardless of what type of treatment is used, the patient is restricted to liquid and soft diet for 6 weeks.

1. Maxillomandibular fixation (max-ill-oh man-dee-bue-lurr fix-eh-shin) is a type of treatment where the upper and lower jaw are held together, keeping the mouth closed, to allow healing (Figure 2). Depending on the age of the child and the type of injury, maxillomandibular fixation may be used for 2 to 6 weeks. 

Figure 2: Two examples of maxillomandibular fixation (MMF). On the left, MMF is achieved with screws and small stainless steel wires. On the right, MMF is achieved using arch bars and stainless steel wires. The arch bars are held to the teeth using small loops of stainless steel wire.

2. Open reduction and internal fixation is a type of treatment where incisions (usually inside the mouth) are made, the broken bones are moved to the correct position, and small plates and screws are used to hold them in place (Figure 3). The plates and screws may be resorbable or non-resorbable. Non-resorbable plates and screws usually provide stronger fixation, but may need to be removed several months later in children. Open reduction and internal fixation may be used in conjunction with maxillomandibular fixation. 

Figure 3: Example of open reduction and internal fixation for a right mandibular body fracture