Jaw disorders

The most common disorders affecting the jaw are temporomandibular joint (TMJ) disorders and jaw dislocation. TMJ disorders include conditions that cause myalgias, arthralgia, headaches, and biomechanical dysfunction in and around the TMJ. They commonly affect young adults and are likely multifactorial in origin. The diagnosis is clinical and based on characteristic features, which include pain, headache, limitations in jaw functioning, and clicking or grinding of the TMJ. Most patients are treated conservatively, e.g., with oral analgesics, behavior modification, heat therapy, and/or splints, and those with refractory symptoms are referred to a specialist. TMJ dislocation can occur unilaterally or bilaterally as a result of extreme mouth opening or direct trauma. Patients present with an inability to close their mouths, impaired speech, and visible facial deformities. The standard treatment is closed reduction. Complications include mandibular fractures, neurovascular injuries, dental injuries, and repeat dislocations. Irreducible TMJ dislocations and mandibular fracture-dislocations usually require specialized treatment (e.g., surgery).

Background ^[1][2]

• Description
  • A syndrome of pain in and dysfunction of the TMJ and muscles of mastication
  • Includes myofascial disorders, temporomandibular disc disorders, arthritis, and autoimmune disorders
• Epidemiology: commonly affects young adults (prevalence 15–31%; peak age 20–40 years) ^[2][3]

Etiology ^[1][4]

The etiology of TMJ disorders (TMDs) is likely multifactorial and involves:

• Behavioral factors: e.g., poor head and/or cervical spine posture, possibly bruxism ^[1][5][6]
• Psychological factors: e.g., depression, anxiety, stress
• Trauma to the TMJ: e.g., cervical spine or jaw injuries
• Abnormal processing of trigeminal nerve pain: e.g., sensitization
• Substance use disorder: e.g., cocaine, MDMA, methamphetamines ^[7][8][9]

Clinical features ^[1][2]

• Pain
  • Typically preauricular
  • Constant, dull, unilateral, with intermittent sharp pain
  • Can spread to the ear, temporal regions, periorbital regions, and/or the mandible
• Aggravating factors
  • Worsened by jaw motion (e.g., chewing)
  • Tenderness on palpation of the TMJ
• Other symptoms
  • Ear discomfort
  • Headache (most often temporal)
  • Clicking, cracking, or grinding of the TMJ
  • Mild trismus, e.g.:
    • Limited jaw opening (occasionally painful)
    • Intermittent locking of the jaw
  • Patients may report bruxism. ^[1][5][6]

Consider a more serious cause of trismus (e.g., head and neck cancer, deep neck infection, tetanus, acute dystonic reaction) if trismus is sustained, progressive, severe, occurs without jaw clicking, or accompanied by atypical symptoms, e.g., lymphadenopathy or oral lesions. ^[10][11]

Diagnosis ^[2]

• TMJ disorders are clinical diagnoses.
• Diagnostic criteria for temporomandibular disorders (DC/TMD) are used clinically and for research. ^[12]
  • Multiple TMD subtypes exist with unique individual criteria.
  • Generally, a TMD is diagnosed if characteristic clinical features (e.g., pain, locking, clicking, headache):
    • Can be localized to the TMJ and nearby anatomic regions
    • Are reproducible with jaw function and/or provocation tests
    • Have been present for at least 30 days
    • Cannot be explained by another disorder
• Imaging (e.g., CT, MRI) is typically used to rule out other diagnoses (e.g., fracture, infection) and if symptoms persist despite conservative treatment.

Management ^[1][2][13]

• Begin a trial of conservative management for all patients.
• If there is no improvement in 2–4 weeks or a severe acute exacerbation, consider imaging, outpatient specialist consultation, and treatment escalation as needed. ^[2]
  • Consult oromaxillofacial surgery (OMFS) if there is a history of TMJ trauma or fracture, refractory severe pain, or persistent pain of unclear etiology for longer than 3–6 months. ^[2]
  • Consult dentistry for underlying dental disorders.

Conservative management

• General measures
  • Soft diet
  • Moist warm compresses
  • Physical therapy and passive stretching exercises
  • Patient education and behavior modification (e.g., stress reduction, avoiding excessive opening of the mandible when yawning)
  • Occlusal splints
• Pharmacological therapy
  • NSAIDs (e.g., naproxen): first-line agents (see “Oral analgesics” for dosages) ^[2]
  • Muscle relaxants (e.g., cyclobenzaprine): generally added for patients with evidence of a muscular component (e.g., muscle spasms, tenderness to palpation) ^[2][13]
  • Inadequate improvement after 2–4 weeks of conservative treatment, NSAIDs, and/or muscle relaxants: Consider adding tricyclic antidepressants (e.g., amitriptyline), benzodiazepines (e.g., diazepam), or anticonvulsants (e.g., gabapentin). ^[2]

Opioids are generally not recommended to treat TMDs. Opioids should only be used for a short period of time in patients with severe pain refractory to nonopioid medication. ^[2]

Invasive management

• Intraarticular corticosteroid injection
• Other injectable agents: intraarticular hyaluronic injections, botulinum toxin injections
• Surgery (rarely required)
  • Indications: if conservative measures and intraarticular injections are unsuccessful and in patients with a history of recent trauma
  • Procedures: arthroscopy, discectomy, total joint replacement

Etiology ^[14][15]

• Significant and/or prolonged mouth opening (e.g., yawning, dental procedures, acute dystonic reaction)
• Direct trauma
• Anatomic predisposition
• Weakness or injury to the TMJ ligaments

Previous TMJ dislocation is a risk factor for recurrent TMJ dislocations. ^[14]

Pathophysiology ^[14][15]

• Anterior TMJ dislocation (most common): The mandibular condyle becomes trapped anterior to the mandibular fossa (can occur unilaterally or bilaterally).
  • With wide mouth opening, the articular surface of the mandibular condyle rotates and glides anteriorly.
  • If the condyle slides past the articular eminence of the mandibular fossa, spasm of the muscles of mastication pulls it superiorly, locking it in place.
• Dislocations in other directions (e.g., posterior, lateral) are rare.

Clinical features ^[14]

• Inability to close the mouth
• Impaired speech
• Pain
• Palpable and/or visible depression in the preauricular space
• Unilateral dislocation: deviation of the jaw to the contralateral side

Bilateral symmetrical dislocations are more common than unilateral dislocations. ^[14]

Diagnosis ^[14]

TMJ dislocation is typically a clinical diagnosis.

• Atraumatic: Routine imaging is unnecessary.
• Traumatic: Obtain imaging to rule out a fracture, e.g., CT face (see “Diagnostics” in “Mandibular fractures”).

Management ^[14][15]

• Initial management: Attempt closed reduction of the mandible if there are no contraindications.
• Aftercare ^[14]
  • Avoidance of wide mouth opening (e.g., during yawning)
  • Soft diet for 1 week
  • NSAIDs or muscle relaxants as needed
  • Warm compresses applied to TMJ
• Disposition ^[14]
  • Most patients can be discharged after successful reduction.
  • Consult OMFS for irreducible TMJ dislocation, non-anterior TMJ dislocations, or mandibular fracture-dislocation.
  • Consult dentistry for dental injuries.

Complications ^[15]

• Mandibular fracture
• Neurovascular injury
• Dental injuries
• Complications of jaw reduction

Indication ^[14][15]

Closed reduction is indicated for clinically apparent anterior TMJ dislocation.

Contraindication ^[14][15]

Concurrent mandibular fracture is the only absolute contraindication to attempting a closed reduction in an emergency setting.

Consult OMFS if there is a mandibular fracture-dislocation.

Equipment ^[14][15]

• Gloves
• Gauze
• Bite block (optional)
• Digit protection: e.g., tongue depressors, finger splints (optional)

Landmarks and positioning ^[14][15]

Positioning

• Sit the patient upright with support for the back and head.
• Face the patient or stand behind them, with the elbows at the level of the patient's mandible or higher.

Approaches

• Intraoral
  • Place the thumbs on the mandibular ridge posterior to the molars.
  • Alternatively, place protected thumbs on the occlusal surfaces of the patient's teeth.
  • Wrap the other fingers along the base of the mandible on either side.
• Extraoral
  • Place the thumbs on the skin overlying the displaced mandibular condyle.
  • Wrap the other fingers along the base of the mandible on either side.

Procedure ^[15]

1. Administer procedural sedation and analgesia (PSA).
2. Consider inserting a bite block for provider protection.
3. With the hands in position, apply steady caudal pressure to the mandible.
4. Guide each mandibular condyle inferiorly and posteriorly into the mandibular fossa.
5. Evaluate mandibular range of motion after the reduction.

If using the intraoral approach, be careful not to injure the thumbs, as the teeth may snap together at the time of reduction. ^[15]

For bilateral TMJ dislocations, it is typically easier to reduce one mandibular condyle at a time rather than both simultaneously. ^[15]

Pitfalls and troubleshooting ^[15]

• Unsuccessful reduction
  • Optimize procedural sedation and analgesia.
  • Ensure proper patient positioning.
  • Consider changing the approach or technique. ^[15]
  • Consult ENT or OMFS for refractory TMJ dislocation.
• Digital injuries: may be sustained by the provider if an intraoral approach is used
  • Prevention: Insert a bite block and protect the thumbs with tongue depressors or finger splints.
  • Management: See “Human bites,” and “Finger injuries.”

Complications of jaw reduction

• Cartilage and/or ligament injury
• Dental injuries
• Redislocation
• Rarely, mandibular fracture

Jaw pain ^[2][14]

• Neuropathic pain: trigeminal neuralgia, postherpetic neuralgia, glossopharyngeal nerve palsy
• Dentalgia: odontogenic infections, dental injuries
• Facial fractures: mandibular fracture
• Intracranial pathology: brain tumor, intracranial hemorrhage
• Headache syndromes: temporal arteritis, migraine
• Otolaryngeal pathology: acute otitis media, sinusitis, parotitis, sialolithiasis
• Referred pain: acute coronary syndrome
• Other: bruxism

Trismus ^[2][14]

• Increased muscle tone: tetanus, acute dystonic reactions, seizures, rabies, hypercalcemia, NMS
• Infections: peritonsillar abscess, deep neck infections
• Tumors: pharyngeal cancer

The differential diagnoses listed here are not exhaustive.