Effect of Anesthetic Gel on Bond Strength of Adhesive Systems

Objectives: the present study aimed to evaluate the effect of a topical anesthetic gel on the micro-tensile bond strength of resin composite to dentin using three adhesive systems. Methods: eighteen non-carious premolars were randomly assigned for three experimental groups and their controls. They were cut to expose cervical dentin and resin composite (Clearfil APX, Kuraray, Japan) was applied on cut surfaces using different adhesive systems for three control groups. The adhesives used were Clearfil Protect Bond (Kuraray, Japan), Clearfil Tri-S Bond (Kuraray, Japan) and Single Bond Plus (3M/ESPE, USA). The experimental groups were contaminated with a topical anesthetic gel (Benzo-jel, Henry Schein Inc., USA) and rinsed with water before the adhesive systems and resin composite were applied. The bonded dentin blocks were cut to obtain 20 resin bonded dentin sticks for each group. The stick specimens were stored in distilled water at 37 degree Celsius for 24 hours before subjected to micro-tensile bond tests using EZ-test (Shimadzu, Japan) at a testing speed of 1 mm/min. All fracture surfaces were examined by a scanning electron microscope to identify the failure modes. Results were analyzed using independent t-test and multiple comparisons Bonferroni's test at the 0.05 significance level. Results: there was no significant differences between the experimental and control groups for all adhesive systems used. Mostly, mixed failure type was observed on fracture surfaces. Conclusion: a topical anesthetic Benzo-jel did not affect the bond strength of the adhesives used in the present study.