Reduction of pain from needle stick in the oral mucosa by topical anesthetics: a comparative study between lidocaine/prilocaine and benzocaine.

OBJECTIVE: The aim of the study was to compare the analgesic effect of a topical benzocaine gel with that of a topical gel mixture of lidocaine/prilocaine (L/P).

METHODOLOGY: Forty individuals took part in the study. Topical anesthetics were applied bilaterally in the maxillary vestibule lateral to the canine. On one side, a mixture of 2.5% lidocaine/2.5% prilocaine (EMLA) was applied. On the opposite side, 20% benzocaine (Topex) was applied as control. The patients had no knowledge as to which side each gel was applied. A 27-gauge needle was inserted through the mucosa to bone contact every minute during a seven-minute period in each area of application. The subjects recorded which side was the least painful, and also registered the grade of pain on a 100 mm VAS scale. Comparisons were made estimating the group difference using the Wilcoxon rank sum test.

RESULTS: After one minute, 87.5% of the subjects reported the L/P side being the least painful. After two to four minutes, 97.5-100% reported the L/P side least painful. After five to seven minutes, 90-95% reported the L/P side least painful. The VAS grading of the pain showed that L/P was significantly (p < 0.05) better in eliminating or reducing the pain.

CONCLUSION: Topical anesthetics based on a combination of lidocaine 2.5% + prilocaine 2.5% are significantly more effective than 20% benzocaine in reducing pain from needle stick in the maxillary vestibular mucosa.