Local Complications of Dental Anesthesia

Local Complications of Dental Local Anesthesia

• Needle Breakage:
  • Causes: Intentional bending by the dentist before injection, sudden unexpected patient movement (especially in children), forceful contact with bone, redirection inside tissue, or "hubbing" the needle.
  • Prevention: Avoid short needles for IANB in adults, 30-gauge needles for IANB, avoid bending needles, avoid inserting needles to the hub unless necessary.
  • Management: Instruct the patient to remain calm, keep mouth open, insert bite block. If visible, remove needle with hemostat. If not visible, refer to an oral and maxillofacial surgeon for surgical removal under general anesthesia (GA), locating the fragment with panoramic and computed tomography scanning.

Paresthesia

• Description: Persistent anesthesia or altered sensation beyond the expected duration of anesthesia due to nerve injury. Patients may feel an "electric shock" or "zap."
• Affected nerves: Inferior alveolar nerve, lingual nerve.
• Causes: Trauma from the needle, contaminated anesthetic solution (alcohol/sterilizing solutions), leading to nerve irritation and edema, and increased pressure in nerve region. Hemorrhage into/around the neural sheath.
• Duration: Often temporary, but potentially permanent.
• Management: Inform and reassure the patient, examine in person, determine degree of paresthesia. Explain that it may persist 2 months to a year or longer before resolving. Record findings on the patient's chart. Suggest regular observation. Avoid re-injecting into the traumatized region. Refer to a specialist if persistent.

Facial Nerve Paralysis

• Mechanism: Anesthetic inadvertently deposited into the parotid gland, affecting the facial nerve. Possible during an IANB or Vazirani-Akinosi nerve block if the needle tip is placed within the parotid gland.
• Symptoms: Temporary loss of motor function on the affected side of the face. Inability to close the eye, drooping of the lip.
• Prevention: Follow standard protocols (needle contact with bone before injection for IANB/V-A block.)
• Management: Reassure patient of transient nature, advise to remove contact lenses. Implement eye protection. Delay or avoid re-anesthetizing the patient.

Ocular Complications

• Causes: Anesthetic solution diffusing through the inferior orbital fissure affecting the extraocular muscles (resulting in diplopia). Accidental intravascular injection harming the central retinal artery. Vasospasm leading to blindness.
• Management: Reassure patient, patch affected eye, "wait and observe" approach. Seek ophthalmologist consultation if unsure about cause.

Trismus

• Definition: Limited mouth opening due to muscle trauma or inflammation.
• Average opening: 13.7 mm (range 5-23mm).
• Causes: Muscle trauma in the infratemporal space following intraoral injections. Local anesthetics can be myotoxic, particularly those with vasoconstrictors. Multiple needle insertions, administering contaminated anesthetic agents (e.g., alcohol), or placing large amounts of anesthetic in limited areas can cause tissue distention.
• Management: Standard care depends on the cause and severity. Consider analgesics, muscle relaxants, and appropriate interventions (e.g., oral antibiotics if appropriate).

Infection

• Cause: Contamination of the needle before injection or improper handling of the needle. Needle passing through an infected area can spread the infection.
• Prevention: Proper preparation of the injection site with antiseptic agents, carefully handling needles avoiding non-sterile surfaces, and using sterile disposable needles.
• Treatment: Trismus management, analgesics, and muscle relaxants. If signs and symptoms persist for 3 days, consider antibiotic treatment.

Hematoma

• Cause: Leakage of blood into tissues due to injection trauma.
• Symptoms: Swelling, bruising, discomfort.
• Prevention: Proper injection technique, minimize needle penetrations.
• Management: Avoid additional dental therapy in the region until the symptoms subside. Apply direct pressure for at least 2 minutes.

Soft Tissue Injury

• Cause: Self-inflicted damage to the soft tissue (lips, tongue, cheeks) due to anesthetic numbness. More common in children and patients with special needs.
• Prevention: Placing a cotton roll between teeth and lip (if the area is numb) and warning the patient against biting or chewing hard, abrasive materials (if applicable).
• Management: Analgesics as needed, antibiotics (rarely), warm saline rinses, and a lubricant (e.g., for lip lesions) to reduce discomfort.

Post-Anesthetic Lesions

• Cause: Trauma to tissue by the needle, local anesthetic solution, swab, or instrument (e.g., rubber dam clamp) that can stimulate latent diseases (e.g., aphthous stomatitis or herpes simplex) present in the tissues.
• Management: Symptomatic treatment, such as topical analgesics.

Pain on Injection

• Causes: Dull needle from multiple injections, rapid deposition of the anesthetic causing tissue damage, or pain caused from a needle with barbs.
• Prevention: Use sharp needles, topical anesthetic, and injection rate below 1.8ml/minute, and ideally at 1 ml/minute.
• Management: No specific treatment is usually necessary.

Edema

• Problem: Abnormal fluid accumulation below the skin, causing swelling and localized pain.
• Causes: Trauma, infection, allergic reaction (angioedema), and hemorrhage.
• Management: Edema from trauma, generally resolves within one to three days (with no treatment), analgesic use for discomfort. Edema from infection, hemorrhage,or allergic reactions require specific treatments (analgesics, antibiotics, antihistamines, blood products, supportive care), depending on the underlying cause and severity of the condition.

Sloughing of Tissues

• Causes: Epithelial desquamation (skin peeling/sloughing) from extended periods of topical anesthetic use. Sterile abscess from prolonged ischemia from an anesthetic containing a vasoconstrictor (e.g., high concentrations of epinephrine)
• Management: Treatment depends on whether sloughing is minor or severe, and is generally supportive.

This quiz covers local complications associated with dental local anesthesia, focusing on issues like needle breakage and paresthesia. It discusses causes, prevention strategies, and management of these complications. Test your knowledge on this important topic in dental practice.