17/05/2025
Inferior Alveolar Nerve Block (IANB) Technique 💉🦷
1. Purpose
✅ To anesthetize the inferior alveolar nerve, including its branches:
• Mental and incisive nerves
• Lingual nerve (indirectly)
• Mandibular teeth to the midline
• Buccal soft tissues anterior to the first molar
• Anterior two-thirds of the tongue and floor of the mouth
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2. Armamentarium
🛠️
• 25 or 27 gauge long needle (32 mm)
• Dental syringe
• 1.8 mL of 2% Lidocaine with 1:100,000 epinephrine (or suitable alternative)
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3. Anatomical Landmarks
📍
• Coronoid notch (greatest concavity on the anterior border of the ramus)
• Pterygomandibular raphe
• Occlusal plane of the mandibular molars
• Contralateral premolars (for orientation)
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4. Needle Insertion Point
🧭
• 6–10 mm above the mandibular occlusal plane
• Slightly lateral to the pterygomandibular raphe
• Approximately 1–1.5 cm medial to the coronoid notch
• At the height of the coronoid notch
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5. Needle Path and Depth
🧪
• Advance the needle slowly along an imaginary line from the premolars of the opposite side
• Target: mandibular foramen on the medial surface of the ramus
• Bone contact should be made at a depth of 20–25 mm
• If no bone is contacted: Withdraw slightly, reposition laterally, and re-advance
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6. Aspiration
🩸
• Always aspirate before injection
• If negative (no blood), proceed
• If positive, withdraw slightly and redirect
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7. Deposition of Anesthetic
💉
• Inject 1.5 mL slowly over 60 seconds near the mandibular foramen
• Withdraw needle slightly (~10 mm) to deposit 0.3 mL for lingual nerve anesthesia
• Optional: administer long buccal nerve block with 0.3 mL near the distal and buccal aspect of the last molar
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8. Signs of Success
🔍
• Numbness in the lower lip (mental nerve)
• Numbness of the anterior tongue and the floor of the mouth (lingual nerve)
• No pain during dental treatment
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9. Common Errors
⚠️
• Too shallow insertion → anesthetic not reaching the nerve
• No bone contact → wrong angle or depth
• Too medial/lateral → anesthetic deposited in incorrect tissue plane
• Injection too low → misses the nerve trunk
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10. Complications
⛑️
• Trismus (if pterygoid muscles are irritated)
• Hematoma (if blood vessels are punctured)
• Transient facial paralysis (if anesthetic is deposited in the parotid gland)
• Needle breakage (if inserted to the hub or sudden movement occurs)
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11. Tips
💡
• Always use landmarks and visualize anatomy
• Use gentle pressure and slow deposition
• If no subjective signs in 5–10 mins, consider reinjection
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