Mandibular Fracture or Broken Jaw: Causes, Symptoms, Treatment, Prevention

A mandibular fracture is a broken jaw or fractured jaw. This is the most common facial injury after broken/fractured nose. A mandibular fracture or broken jaw is the tenth most common fracture in human beings. The cause of mandibular fracture or any other fracture for that matter is direct trauma or force to the mandible or jawbone. Men are thrice more likely to sustain a mandibular fracture or broken jaw than women.

The mandible or the jawbone is the main bone and the largest bone of the lower region of the face. The primary areas of the mandible bone include the body (which extends from the chin to the jaw angle) and the rami, which are the two upward branches of the mandible.

• Assaults or getting into a physical fight with someone where someone punches hard on the face can result in mandibular fracture or broken jaw.
• Motor vehicle accidents.
• Injuries, particularly those incurred while playing sports.
• Falling and landing on the face can also cause mandibular fracture or broken jaw.

• Jaw pain is the commonest symptom experienced in mandibular fracture or broken jaw.
• There is swelling on the jaw.
• There is malocclusion where the teeth are misaligned or do not fit together properly when the upper and lower jaws are closed.
• The teeth and the area of the fracture become very sensitive to touch.
• Patient with mandibular fracture or broken jaw has difficulty in completely opening the jaw.
• Patient has symptoms of difficulty in speaking with mandibular fracture or broken jaw.
• Deformity can be seen in the jaw region.
• There may be numbness of the lower lip or chin due to nerve damage in the mandible.
• Patient may also have lost some teeth or may have some loose teeth.
• There may be bleeding in the mouth or there could be a change in the normal teeth alignment. Patient can also have bruising under the tongue.
• There can also be a cut in the ear canal from the backward movement of the fractured jawbone.

Patient should seek immediate medical care if he/she has suffered an injury after which their teeth do not fit together correctly, or if there is swelling, trouble speaking and bleeding inside the mouth. The evaluation of the jawbone injury should be done at the hospital and the patient should get someone else to drive him/her to the hospital and not drive themselves.

One of the serious outcomes of mandibular fracture is difficulty breathing from the loss of support to the tongue. So, if the patient is having any difficulty in breathing, then it needs to be addressed immediately.

This classification is the most useful, as the treatment and the symptoms depend on the location of the mandibular fracture or broken jaw. The jaw bone or the mandible is divided into the following regions:

• Alveolar.
• Condylar.
• Ramus.
• Coronoid process.
• Angle of mandible.
• Body (premolar and molar areas).
• Parasymphysis.
• Symphysis.

Alveolar Fracture of the Jaw Bone: This type of mandibular fracture or broken jaw involves the alveolus, which is the alveolar process of the mandible.

Condylar Fracture of the Jaw Bone: This type of mandibular fracture or broken jaw is classified by location when compared to the ligament capsule, which contains the temporomandibular joint (extracapsular or intracapsular ), dislocation, i.e. if the condylar head has pulled out of the socket and neck of the condyle fractures, e.g. non-displaced, extracapsular, neck fracture.

Coronoid Process Fracture of the Jaw Bone: As the coronoid process of the jaw bone is located deep into various structures, (including the zygomatic complex), it rarely is fractured on its own. The fracture of the coronoid process often occurs with fracture of the zygomatic complex or arch or other mandibular fractures.

Ramus Fracture of the Jaw Bone: Ramus fractures involve an area which is bounded inferiorly by an oblique line that extends from the region of the lower third molar to the posteroinferior attachment of the masseter muscle.

Fracture of Angle of the Mandible: The angle of the mandible is formed by the body of the mandible and the ramus. Angle fractures of the mandible are those which involve a triangular area that is encircled by the anterior border of masseter muscle and a slanting groove which travels from the area of the lower third molar to the posteroinferior attachment of the masseter muscle.

Body: Mandibular body fractures are those which involve an area that is bounded anteriorly by the parasymphysis and posteriorly by the anterior border of the masseter muscle.

Parasymphysis Fracture of the Jaw Bone: Parasymphyseal fractures are those fractures where the fracture site consists of an area that is surrounded on both sides by vertical lines present away from the canine tooth.

Symphysis Fracture of the Jaw Bone: Symphyseal fractures are linear fractures which travel in the midline of the mandible.

Mandibular fractures or broken jaw are also classified depending on condition of the fragments of the bone at the site of fracture and also on the presence of communication with the outside environment.

Simple Mandibular Fracture: In this type of mandibular fracture or broken jaw, there is complete transection of the bone with very less fragmentation at the site of the fracture.

Comminuted Mandibular Fracture: This type of mandibular fracture or broken jaw is the opposite of a simple fracture. In comminuted fracture, the jaw bone gets shattered into multiple fragments or patient will have secondary fractures along with the main fracture lines. The causes of comminuted fractures commonly are high velocity injuries.

Greenstick Mandibular Fracture: These are incomplete fractures of bone that is flexible; and because of this, they usually occur only in children. Greenstick fracture usually has limited mobility.

Compound Mandibular Fracture: In this type of mandibular fracture or broken jaw, there is communication with the external environment that can occur through the facial skin or through the oral cavity. If there is involvement of the tooth-bearing portion of the jaw in mandibular fractures, then they are known as compound fractures, as there is communication with the oral cavity through the periodontal ligament. In cases of more displaced fractures, there will be obvious tearing of the alveolar and gingival mucosa.

Treatment also depends if the fracture has occurred in the tooth bearing part of the mandible and if it is edentulous (no teeth) or dentate. Wiring of the teeth is done to stabilize the fracture; so, treatment depends on whether it is edentulous mandible i.e. no teeth or whether there are teeth present. If the edentulous mandible is lesser than 1 cm in height, then there are additional risks, as the blood flow from the marrow gets reduced and the healing bone is dependent on the blood supply from the periosteum, which encircles the bone. If a child suffers from mandibular fracture with mixed dentition, then there is different treatment protocols required.

Displacement is the degree or extent of the separation between the bone segments. If the separation is great, then it is more difficult to bring (approximate) the bone segments back together.

Favorability for posterior body and angle fractures, if the fracture line angle leans back, then the muscles help in bringing the fracture segments together and this type of mandibular fracture or broken jaw is known as favorable. If the angle of the fracture is tilting to the front, then it is known as unfavorable mandibular fracture or broken jaw.

A physical exam is conducted and x-rays are ordered. During the physical exam, the doctor will carry out a general inspection of the patient’s facial swelling, bruising and deformity. Then the doctor will examine or feel the jawbone through the skin. The mandible or the jaw bone is assessed. After the external exam is done, an internal exam is carried out where the doctor will look inside the mouth. The patient is asked to bite down, so the doctor can check the patient’s teeth for alignment. The stability of the mandible or jaw bone is checked. Tongue blade test is carried out where tongue blade/tongue depressor is placed between the patient’s teeth and checked whether the patient is able to hold the blade in place.

Panoramic x-ray done completely around the jaw is the best screening test to asses for mandibular fracture or broken jaw. If the initial report is negative, then CT scan can be done to look for mandibular fracture.

Conservative treatment for mandibular fracture or broken jaw consists of application of ice to the jaw. This will help in controlling the swelling when the patient is on the way to the doctor. In some cases, a paper cup may be needed to spit blood or to catch the drool of the patient.

Medical Treatment for Mandibular Fracture or Broken Jaw: Many of the patients suffering from jaw pain after an injury will not have broken jaw and are usually prescribed pain medications and are instructed to eat a soft diet. Further evaluation is needed for patients who actually have mandibular fracture (broken jaw). Many mandibular fractures or broken jaw are associated with tissue damage and gum problems and should be considered as open fracture. Treatment is started with antibiotics. Patient is given a tetanus shot and pain killers are prescribed. If the mandible fracture is stable, then treatment consists of wiring the upper and lower teeth together which is done by oral and maxillofacial surgeon.

Surgery for mandibular fracture or broken jaw is needed for unstable fractures where plates are used across the fracture, so that the patient has normal movement of the jaw bone or mandible and is able to eat sometime after surgery. Older mandibular fractures are thought to have higher infection and non-union rates. Most of the mandibular or jaw fractures need surgery and due to this reason, it is important to regularly follow up with your surgeon, take the complete antibiotics course as prescribed and follow dietary recommendations.

As majority of the mandibular fracture or broken jaw occur as result of assaults and motor vehicle accidents, the best way to prevent them is driving carefully and choosing your company wisely. During sports activities, it is strictly advisable to wear protective gear.

Mandibular fracture or broken jaw, which are stable do not need surgery and can be managed with pain medications and dietary changes. Depending on the location and nature of the fracture, surgery may be needed to fix the fracture. The healing time required is around 4 to 6 weeks for a routine mandible fractures where rigid internal fixation (RIF) or maxillo-mandibular fixation (MMF) is used. In mandible fractures, patients receiving MMF will have more weight loss and it takes a longer time for them to regain their mouth opening; whereas, higher infection rates are associated with patients receiving rigid internal fixation (RIF).

The commonest long-term complications from mandibular fracture or broken jaw and its surgery is malocclusion, loss of sensation in the mandibular nerve and loss of teeth in the fracture line. Condylar fractures have increased risk of malocclusion, which in turn depends on the degree of dislocation/displacement of the jaw. There is increased risk of late-term osteoarthritis if the mandible fracture is intracapsular. Condylar fractures in children have higher rates of ankylosis with chances of disturbance in growth. In very rare cases, mandibular fracture or broken jaw can lead to Frey’s syndrome.

Overall, the prognosis is good if the patient follows doctor’s instructions, the recommended diet and takes the required antibiotic course and regularly follows up.