A patient achieves profound anesthesia of the lip and tongue after an IANB injection, but the tooth still responds to the cold test. What is the BEST supplemental technique to achieve pulpal anesthesia?

Correct answer: A. Buccal infiltration with 4% articaine

• A. CORRECT. Profound lip numbness confirms the IANB was correctly placed and the inferior alveolar nerve is anesthetized. The remaining pulpal sensitivity (a 'hot tooth') is due to accessory innervation or central sensitization. The evidence-based supplemental technique is buccal infiltration with 4% articaine, which has a high bone diffusion capacity and produces pulpal anesthesia even through dense cortical bone.
• B. Repositioning toward bone suggests a missed block — but profound lip numbness confirms the block was successful. This approach does not address the accessory innervation problem.
• C. A repeat IANB with lidocaine after 30 minutes is less effective for a hot tooth — the inferior alveolar nerve is already blocked; the problem is not the injection site but accessory innervation.
• D. Intraligamentary injection can help but is considered a second-line option with lower success rates than articaine buccal infiltration for irreversible pulpitis.