Effect of chlorhexidine on bonding durability of two self-etching adhesives with and without antibacterial agent to dentin

Abstract

Background: Considering the possibility of remaining bacteria in the cavity or invading via

microgaps, the use of antibacterial agents in adhesive restoration may be beneficial. This study

evaluated the effect of chlorhexidine on immediate and long-term shear bond strength of adhesives

with and without antibacterial agent to dentin.

Materials and Methods: In this in vitro study, the occlusal surfaces of 80 intact human premolars

were removed to expose the flat midcoronal dentin. The teeth were assigned to four groups. Two

adhesive systems, Clearfil SE Bond (SE) and Clearfil Protect Bond (PB) were used according to

manufacturer’s instructions as the control groups. In the experimental groups, 2% chlorhexidine

was applied prior to acidic primer of two adhesives. Then, resin composite was applied. Half of the

specimens in each group were submitted to shear bond test after 24 h without thermocycling, and

the other half were submitted to water storage for 6 months and thermocycling before testing. The

data was analyzed using three-way analysis of variance (ANOVA) and t-test (a = 0.05).

Results: Chlorhexidine application significantly decreased the initial bond strength (BS) of the two

self-etch adhesives to dentin (P < 0.05). There was a significant reduction in BS of SE and PB after

aging compared to initial bonding (P < 0.05). However, there was no significant difference between

BS of the control and chlorhexidine-treated groups for the tested adhesives after aging. PB showed

a lower BS than SE in two time periods (P < 0.05).

Conclusion: Chlorhexidine was capable of diminishing the loss of BS of these adhesives over

time. However, considering the negative effect of chlorhexidine on the initial BS, the benefits of

chlorhexidine associated with these adhesives cannot possibly be used.

Key Words: Antibacterial monomer, bond strength, chlorhexidine, self-etch adhesive