A patient has a confirmed inferior alveolar nerve (IAN) block — the lower lip and lateral tongue are profoundly numb — but still reports pain during attempted extraction of a mandibular molar. What is the most appropriate next step?

When an IAN block is anatomically successful (lip and tongue confirmed numb) but pulpal anesthesia is incomplete, the most effective supplemental technique is buccal infiltration with 4% articaine with 1:100,000 epinephrine. Articaine is unique among amide local anesthetics: its thiophene ring allows superior diffusion through dense cortical bone, making it significantly more effective than lidocaine for supplemental mandibular infiltration. Clinical trials show 4% articaine buccal infiltration achieves pulpal anesthesia in approximately 58% of cases where the IAN block was insufficient. In comparison, 2% lidocaine infiltration has poor cortical bone penetration in the posterior mandible and is generally ineffective. Repeating the IAN block rarely helps if the first was technically confirmed. Intraligamentary or intrapulpal injection may also be considered as alternatives.