RESUMO
INTRODUCTION: Local anesthetics can be buffered to a physiological pH before injection to decrease the time of onset and reduce injection pain. METHODS: Thirty subjects with intact maxillary canines were included. The subjects randomly received, in a double-blind manner, 1 of the 3 maxillary infiltration injections of 1.8 mL 2% lidocaine with 1:100,000 epinephrine and 2% lidocaine with 1:100,000 epinephrine buffered at 5% and 10% with sodium bicarbonate by volume at 3 separate appointments. Pain on needle penetration and deposition of anesthetic solution was recorded by using a Heft-Parker visual analogue scale. Anesthetic onset was determined by 2 consecutive negative responses to electronic pulp test. RESULTS: The mean anesthetic onset for nonbuffered anesthetics was 119 seconds, 116 seconds for the 5% buffered solutions, and 121 seconds for the 10% buffered solutions. There was no significant difference between the 3 groups. There was also no significant difference in pain on needle penetration or anesthetic deposition between the 3 anesthetic solutions tested. CONCLUSIONS: Two percent lidocaine with 1:100,000 epinephrine buffered with 5% or 10% sodium bicarbonate did not differ from nonbuffered solutions in anesthetic onset or injection pain in maxillary infiltrations of canines with healthy pulps.
