Anesthetic efficacy of a primary articaine infiltration and a repeat articaine infiltration in the incisive/mental nerve region of mandibular premolars: a prospective, randomized, single-blind study.

The authors conducted a prospective, randomized, single-blind study to determine the degree of pulpal anesthesia obtained with a primary infiltration of 1 cartridge of articaine in the incisive/mental nerve region of the mandibular second premolar and to determine the anesthetic efficacy of a repeat articaine infiltration 20 minutes after the primary infiltration. One hundred asymptomatic adult subjects randomly received 2 sets of injections consisting of a primary mandibular second premolar infiltration of 1 cartridge of 4% articaine with 1:100,000 epinephrine plus a repeat infiltration 20 minutes later (using the same volume of articaine) or a mock repeat infiltration in 2 separate appointments spaced at least 1 week apart. The authors used an electric pulp tester to test the first molar, premolars, canine, and incisors for anesthesia in 4-minute cycles for 120 minutes. The success rates of the initial infiltrations for the first molar, canine, and incisor teeth ranged from 59% to 19%. The premolar success rates were moderately successful (ie, 80%-87%), but anesthesia declined after 20-25 minutes. The repeat infiltration at 20 minutes significantly increased the success rate (92%-94%) and the duration of pulpal anesthesia for the premolars. The initial infiltration was not effective in anesthetizing the first molar, canine, or incisor teeth and was only moderately successful in the premolars. Although the repeat infiltration significantly increased the success rate and duration in the premolars, the initial infiltration success rates were not high enough to support the use of this regimen as a combined anesthetic technique.