Efficacy of Six Local Anesthetic Formulations Following Mandibular Buccal Infiltration

Objective: The goal of this randomized, double-blind controlled study was to determine the relative pulpal anesthetic properties of six commonly marketed local anesthetic formulations: 4% articaine HCl with 1:100,000 epinephrine (A100), 4% articaine HCl with 1:200,000 epinephrine (A200), 2% lidocaine HCl with 1:100,000 epinephrine (L100), 4% prilocaine HCl with 1:200,000 epinephrine (P200), and 3% mepivacaine without vasoconstrictor (Mw/o), and 0.5% bupivicaine with 1:200,000 epinephrine (B200) following mandibular infiltration.

Methods: Using a repeated treatment design, this trial enrolled 12 healthy volunteers (5M/7F; mean age 25.6 yrs). At screening, informed consent, medical history, physical examination, vital signs, urine pregnancy testing were obtained. Mandibular infiltrations (6 sessions per subject) were administered into the buccal fold adjacent to the mandibular first molar on the same side using an injection volume of one half cartridge (0.9 mL) using an aspirating dental syringe and a 30 gauge short disposable needle and no topical anesthetic. Anesthetic efficacy over twenty minutes was determined by changes in sensory threshold of the dental pulp following electric tooth stimulation (Kerr Vitality Scanner Model #2006).

Results: Pain upon injection, measured on a 100 mm VAS, was reported as follows: 43.1 (B200), 39.8 (L100), 37.9 (A100), 35.3 (A200), 31.1 (Mw/o), and 27.3 (P200). Maximum mean change in EPT recordings for the 6 formulations was 47% (L100), 49.7% (B200), 51.2% (P200), 70.1% (Mw/o), 74.3% (A100, p<.05 vs L100) and 81.1% (A200, p<.05 vs L100)). Cumulative anesthetic success rating (EPT=80) for the twenty minutes of assessment (12 subjects x 20 min) was 8/240 (B200), 10/240 (L100), 38/240 (P200), 42/240 (Mw/o), 78/240 (A100), and 79/240 (A200). Adverse reactions were minor and not formulation dependent.

Conclusion: This study indicates that the efficacy of mandibular infiltration varies with the local anesthetic administered. The articaine formulations provide the greatest successful anesthesia.

Supported through UPitt Depart. Anesthesiology.