Besides altercations, motor vehicle accidents are the most common cause of fractures of the mandible. In fact, in one study, motor vehicle accidents accounted for between 47 and 48 percent of all mandible fractures. Running distantly behind were work-related injuries at 7 percent, sporting accidents at 4 percent and falls at 7 percent.
Most fractures of the mandible occur in the body of the bone with fewer fractures in the condyle (ball) and angle of the mandible. More fractures occur in the symphysis of the bone with only 4 percent of fractures occurring in the ramus. In most auto accidents, the symphysis, the presenting part of the chin, gets broken. In assaults, it’s the angle of the jaw that gets fractured.
Mandible fractures do not often happen in isolation. Almost half have some other kind of injury, such as lacerations to the head and neck, closed head trauma, skull fractures, eye injuries, mid-face injuries and nasal fractures, among others. In fact, 3 percent of those with mandibular injuries died before the fracture to their mandible could be treated.
Half of all patients with a mandible fracture have a single fracture; 37 percent have 2 fractures and 9 percent suffer from three or more fractures. Simple fractures are closed and do not have a wound in the mouth or on the skin. Open or compound fractures involve an opening and extrusion of bone through a wound. Comminuted fractures are those were the bone has become crushed or splintered.
Historically speaking, a closed mandibular fracture was treated with closed reduction and wires to keep the bones together. This required keeping the mandible in its anatomic position for at least six weeks. This generally resulted in poor nutrition, difficulty with the person’s airway, poor dental hygiene and difficulty talking or working during that period of time. Extreme weight loss was common.
Now, surgical repair with rigid and partially-rigid fixation of the mandible fractures are allowing patients a chance to have return of speech, better comfort and earlier return to work. This treatment has been found to be more cost effective than the previous form of treatment.
Closed reduction can be used for nondisplaced fractures while open reduction is better for open fractures and those that are displaced. Grossly comminuted fractures are best treated with closed reduction as are fractures seen in children. Open fractures in children can damage healthy tooth buds making dentition poor later in life. In open fractures, it is recommended to use resorbable fixatives or wires located along the inferior aspect of the mandible. Open reduction of the mandible is necessary whenever there is a displaced, unfavorable situation with the fracture or whenever there are edentulous mandibles that are atrophic and have very little normal cancellous bone in the mandible. Healing would be delayed if the treatment involved a closed procedure.
The important part of mandibular fractures is that they often cause the teeth to become misaligned. This means the teeth must be wired into a proper position before surgery or external fixation is done. This assures proper alignment of the teeth.