Evaluation of articaine infiltration location on the success rate of mandibular lateral incisor anesthesia: A prospective crossover randomized clinical trial study.

Introduction: Effective anesthesia of the mandibular lateral incisor is challenging. This study compared the efficacy of lingual infiltration alone versus combined labial and lingual infiltration using 4% articaine with 1:100,000 epinephrine.

Methods: In this prospective, randomized, crossover clinical trial, 50 healthy volunteers received two infiltration techniques: (1) lingual infiltration only (3.6 mL total via two 1.8 mL injections plus a mock buccal injection), and (2) combined labial and lingual infiltration (1.8 mL each; 3.6 mL total plus a mock lingual injection). Anesthetic success was evaluated by: 1) absence of response to maximal electronic pulp tester stimulation, 2) sustained anesthesia defined as no response within 16 minutes lasting 42 minutes, and 3) anesthesia onset time (first of two consecutive no-response readings). Pain during injection was assessed via the 170-mm Heft-Parker visual analog scale (VAS). Statistical tests included McNemar's, Wilcoxon signed-rank, Friedman, and Dunn's test.

Results: The combined technique produced an equal or higher success rate (P ≤ 0.05), significantly greater sustained anesthesia (P < 0.05), and a significantly shorter onset time (P < 0.05) compared with lingual infiltration alone. Labial infiltration was associated with higher pain scores, especially during solution deposition (P < 0.05).

Conclusions: The combination of labial and lingual infiltration with 4% articaine and 1:100,000 epinephrine significantly improves the anesthetic success and duration for the mandibular lateral incisor, although it is associated with increased injection-related pain.