Definition

A mandible fracture refers to a break in the mandible, the V-shaped lower jawbone. Mandible fractures are among the most common facial bone injuries seen in emergency settings.

The mandible is a complex structure. It plays a key role in food digestion, speech, and facial expressions. Mandible fractures often occur in more than one place, posing a risk for bacterial contamination from the mouth. 

Surgical intervention is often necessary due to the complex anatomy of the mandible and its crucial role in the body's functions, such as protecting the airway and maintaining dental structure.

Causes

Mandible fractures can result from a variety of factors depending on age, population demographics, environmental and socioeconomic conditions, and cultural practices. 

Common causes of mandible fractures include:

• Motor vehicle accidents
• Physical violence, such as from fights
• Gunshot injuries
• Sports accidents
• Industrial or workplace accidents
• Falls from heights
• Medical conditions that weaken bones, making them more prone to fractures.

Risk Factor

In urban settings, physical violence is a more frequent cause of mandibular fractures than motor vehicle accidents. Males are three times more likely to suffer from mandibular fractures than females, with most cases occurring during the third decade of life. These fractures are rare in children under the age of six.

Having lower wisdom teeth also increases the risk of mandibular fractures. Additionally, patients with these fractures who have wisdom teeth are more likely to develop infections.

Symptoms

Patients with mandibular fractures may experience the following symptoms:

• Persistent pain in the lower jaw, often due to movement of broken bone fragments.
• Tingling or a stinging sensation in the chin area if the mental nerve is affected.
• Malocclusion, where the alignment of upper and lower teeth is disrupted.
• Facial asymmetry.
• Visible changes in jaw shape.
• Reduced range of motion in the temporomandibular joint (TMJ) near the ear.
• Difficulty swallowing (dysphagia).
• Trismus, a condition where muscle spasms prevent the mouth from opening.
• Tooth damage and misalignment.
• External ear canal injuries.
• Swelling and bruising around the face and jaw.
• Grinding or crepitus sounds in the fractured mandible.
• Bleeding in the jaw, mouth, or facial area.

Diagnosis

When diagnosing a mandibular fracture, the doctor will perform a comprehensive examination to assess the patient's stability. If the patient is unstable, stabilizing their condition takes priority.

Initial Examination

The doctor will assess whether the patient's airway is obstructed, which may result from the fracture or bleeding in the oral cavity that could enter the airway.

Mandibular fractures may be associated with other injuries, so the cervical spine and brain are also checked. Vital signs such as blood pressure, pulse, breathing, temperature, pain level, nerve function, and consciousness are evaluated.

Medical Interview

The doctor may ask the patient or their accompanying family members the following questions:

• The time and mechanism of injury (e.g., traffic accident, violence).
• The patient’s current symptoms, such as pain or bleeding.
• The patient’s past medical history.
• Any ongoing treatments the patient is receiving.

Physical Examination

Several physical examinations may be performed, including:

• Clinical examination: Focused on the face, teeth, and mouth.
• Nerve examination, checking for:
  • Changes in sensation
  • Pupillary reflexes
  • Vision
  • Eye movement
  • Tongue movement
  • Facial expression
  • Chewing muscles.
• Observation of external signs, assessing for:
  • Bruising, swelling, bleeding, and blood clots
  • Grinding sounds in the broken bones
  • Limited jaw movement
  • Tooth damage, such as loose, broken, or missing teeth
  • Checking for damage to other limbs.

Diagnostic Tests

Imaging or radiological tests are required to confirm a bone fracture. The following examinations may be conducted:

• X-rays of the mandible: Taken from multiple angles to detect abnormalities.
• Panoramic dental scans: Used to evaluate the cartilage, with CT scans also employed when facial fractures are suspected.
• Chest X-ray: Performed on unconscious patients or those who have lost teeth to ensure no teeth have entered the airway.
• Laboratory tests: Conducted if necessary or prior to surgical procedures.

Management

Initial Treatment

The primary focus of the physician is to stabilize the patient's condition and address any immediate life-threatening emergencies. The patient will be positioned supine, and obstructions in the mouth or airway, such as foreign objects, loose teeth, blood, mucus, or clots, will be cleared. The neck will be stabilized using a cervical collar. In cases of severe bleeding or injury to the cervical spine or head, these conditions will be prioritized.

To prevent bacterial infections that could further complicate the patient's situation, antibiotics may be prescribed. If the wound is not clean, a tetanus vaccination may also be considered. Pain relief medication will be administered to manage discomfort.

Fracture Treatment

The main goal of fracture management is to restore the mechanical integrity of the fractured bone, promoting proper healing. Additionally, the restoration of muscle function surrounding the fracture site is also a key focus.

The treatment process involves repositioning the bone fragments to their correct anatomical alignment, followed by immobilization. The doctor will assess whether surgical intervention is required to treat the fracture.

Complications

In most cases, the prognosis for mandibular fractures is favorable, especially when the fracture is not associated with other injuries. However, some patients may experience additional complications, such as injuries to the head, neck, or eyes, as well as fractures in the facial bones, nose, or spine.

The most frequently observed complication is infection, which may increase the likelihood of the fracture not healing within nine months, or healing improperly.

Other possible complications include nerve damage that affects the face and jaw region, as well as dental issues.

Prevention

Adopting safe driving practices can help reduce the risk of accidents. Wearing a helmet or seatbelt and adhering to speed limits are essential. In workplaces with potential hazards, such as industrial environments, it is crucial to use personal protective equipment to prevent injuries.

When to See a Doctor?

Fractures are emergencies that require prompt treatment. If you or someone else sustains a fracture, immediate transportation to the emergency room is necessary for proper care.

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