Definition

Dislocation of the temporomandibular joint is a condition characterized by the displacement of the joint connecting the condylar process of the mandible (the bony protrusion of the jaw) with the temporal fossa (the surface of the skull). This condition can affect either one or both joints.

Typically, the condylar process of the mandible and the temporal fossa align to form what is known as the temporomandibular joint. These bones are connected by elastic connective tissue (ligaments), tendons (thick muscle fibers), and muscles. This network of structures ensures that the temporomandibular joint remains in place and moves flexibly according to its function. Dislocation of the temporomandibular joint occurs when its supporting components—ligaments, tendons, and muscles—experience weakness or damage, leading to a lack of structural support for the connection between the condylar process and the temporal fossa.

Dislocation of the temporomandibular joint is relatively common, occurring in about 7% of the population. It can affect individuals of all age groups, particularly those between 20 and 40 years old. Dislocation of both joints is more frequent than that of a single joint and can be acute or recurrent. Trauma to the face is the most common cause of dislocation.

Causes

The causes of temporomandibular joint dislocation can be categorized as either non-traumatic or traumatic.

Non-traumatic causes include:

• Excessive and forceful mouth opening, such as when laughing, yawning, singing, or opening the mouth too wide. This can overstretch the supporting tissues, causing the joint to shift from its position.
• Muscle spasms
• Repeated chewing
• Ligament weakness
• Connective tissue disorders
• Muscle rigidity, such as in tetanus
• Medication side effects
• Post-procedural stretching of the joint, such as during dental treatments, intubation, or bronchoscopy

Traumatic causes, which are more common, include acute facial trauma resulting from accidents or falls. Such trauma can damage ligaments, muscles, and the mandible, leading to direct injury to the temporomandibular joint and its dislocation.

Read more: Ligament Injuries - Definition, Cause, Symptoms  and Treatment

Risk factor

Risk factors for temporomandibular joint dislocation include:

• A history of previous dislocations
• Structural bone abnormalities
• Connective tissue disorders affecting joint integrity
• Advanced age
• Neurological disorders
• Changes in dental alignment
• Habits such as teeth grinding and chewing hard foods
• Inflammatory joint diseases like osteoarthritis or rheumatoid arthritis
• Jaw and facial injuries
• Psychological issues such as stress
• Misaligned bites

Symptoms

Common symptoms of temporomandibular joint dislocation include acute pain in the front of the ear, which intensifies with jaw movements such as chewing, mouth opening, speaking, or laughing. Additional symptoms may include:

• Misalignment of the bite, with the upper and lower teeth not aligning properly
• Difficulty speaking and swallowing
• Forward protrusion of the jaw
• Difficulty moving the jaw and closing the mouth
• Drooling
• Stiffness when moving the jaw
• Pain in the face and jaw
• Facial asymmetry

Diagnosis

To diagnose temporomandibular joint dislocation, the doctor will gather information through patient history and physical examination.

Medical history

The doctor will inquire about:

• Current symptoms
• Medical history
• Regular medication use
• Family history of similar conditions

Physical examination

Following the medical interview, the doctor will perform a general and specific physical examination. General physical examination includes measuring blood pressure, respiratory rate, pulse, and body temperature. The specific examination involves inspection and palpation of the temporomandibular joint.

Inspection involves observing the front of the ear for any protrusions or skin indentations, assessing facial symmetry, and checking the alignment of the upper and lower teeth. Palpation involves feeling for tenderness, indentations, and protrusions in the temporomandibular joint area. The presence of dislocation in one or both joints is also assessed. Through medical history and physical examination, the diagnosis of temporomandibular joint dislocation can be confirmed.

Additional tests

For a clearer understanding, radiological tests may be performed, such as:

• X-ray: To detect the presence of dislocation
• CT Scan: Typically used if there is overlap between dislocation and bone fractures
• MRI (Magnetic Resonance Imaging): To assess the soft tissue structures of the joint, such as ligaments and muscles. MRI can be used to evaluate recurring dislocations and determine the underlying causes.

Management

In managing temporomandibular joint dislocation, the doctor will first assess the overall stability of the patient to identify any life-threatening conditions. Components assessed include airway obstruction, breathing, and adequate oxygen supply to the body.

Next, analgesics are administered to alleviate pain, which can range from mild to severe in temporomandibular joint dislocation. Muscle relaxants are also given to ease muscle stiffness due to the joint displacement. Additionally, the doctor will use an elastic bandage to stabilize the joint and prevent further displacement.

The primary goal in managing temporomandibular joint dislocation is to reposition the displaced joint to its normal position. This can be achieved through specific repositioning techniques. If this procedure is unsuccessful, surgical intervention may be necessary, particularly in cases with bone fractures or significant ligament weakness. Surgery aims to strengthen and stabilize the supporting ligaments.

Complications

Temporomandibular joint dislocation can be acute or chronic. Chronic dislocations can lead to complications such as damage to ligaments and other supporting tissues, potentially resulting in joint disease. Additionally, dislocation of the upper joint can cause damage to the outer ear canal, leading to hearing impairment. Nerve damage in the face and hearing can also occur. Vascular injuries may also be observed in temporomandibular joint dislocation cases.

Prevention

To prevent temporomandibular joint dislocation, consider the following measures:

• Avoid opening the mouth too wide when yawning
• Place a fist under the chin to prevent excessive mouth opening during yawning
• Use mouthguards during sports and recreational activities
• Always wear a helmet while driving

When to see a doctor?

If you experience pain in the front of the ear accompanied by difficulty speaking, opening the mouth, or chewing, it is advisable to consult a specialist in oral and maxillofacial surgery promptly to determine the cause.

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