Efficacy of Benzocaine 20% Topical Anesthetic Compared to Placebo Prior to
Administration of Local Anesthesia in the Oral Cavity: A Randomized Controlled
Trial.
Author(s): de Freiras GC(1), Pozzobon RT(2), Blaya DS(1), Moreira CH(2).
Affiliation(s): Author information:
(1)Franciscan University Center, Santa Maria, Rio Grande do Sul, Brazil.
(2)Federal University of Santa Maria, Rio Grande do Sul, Brazil.
Publication date & source: 2015, Anesth Prog. , 62(2):46-50
The aim of the present study was to compare the effects of a topical anesthetic
to a placebo on pain perception during administration of local anesthesia in 2
regions of the oral cavity. A split-mouth, double-blind, randomized clinical
trial design was used. Thirty-eight subjects, ages 18-50 years, American Society
of Anesthesiologists I and II, received 4 anesthetic injections each in regions
corresponding to the posterior superior alveolar nerve (PSA) and greater palatine
nerve (GPN), totaling 152 sites analyzed. The side of the mouth where the topical
anesthetic (benzocaine 20%) or the placebo was to be applied was chosen by a flip
of a coin. The needle used was 27G, and the anesthetic used for administration of
local anesthesia was 2% lidocaine with 1:100,000 epinephrine. After receiving the
administration of local anesthesia, each patient reported pain perception on a
visual analog scale (VAS) of 100-mm length. The results showed that the topical
anesthetic and the placebo had similar effects: there was no statistically
significant VAS difference between the PSA and the GPN pain ratings. A higher
value on the VAS for the anesthesia of the GPN, relative to the PSA, was observed
for both groups. Regarding gender, male patients had higher values on the VAS
compared with female patients, but these differences were not meaningful. The
topical anesthetic and the placebo had similar effects on pain perception for
injection of local anesthesia for the PSA and GPN.
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