Evaluation of Shear Bond Strength of Total- and Self-etching Adhesive Systems after Application of Chlorhexidine to Dentin Contaminated with a Hemostatic Agent

STATEMENT OF THE PROBLEM: Hemostatic agents may influence the bond strength of different bonding agents. Also, chlorhexidine has shown positive effects on bond strength values and their combination effect has not been reported yet. PURPOSE: The aim of this study was to evaluate the effect of contamination with a hemostatic agent on shear bond strength (SBS) of total- and self-etching adhesive systems and the effect of chlorhexidine application after removal of the hemostatic agent. MATERIALS AND METHOD: In this experimental study, the occlusal enamel of each sixty caries-free mandibular molars was removed and their midcoronal dentin was exposed. The specimens were then mounted in auto-polymerizing resin 1mm apical to CEJ. Then, the specimens were divided into 6 groups (n=10) based on contamination with a hemostatic agent (H), application of chlorhexidine (CHX) and the adhesive system used; and then were classified as Group 1: Adper Single Bond (ASB); Group 2: H+ASB; Group 3: H+0.2% CHX+ASB; Group 4: Clearfil SE Bond (CSB); Group 5: H+CSB; Group 6: H+0.2% CHX+CSB. Then, composite resin rods (4×2 mm) were built up on the dentin surfaces and after thermocycling, the SBS (MPa) was evaluated. Statistical analysis was performed using two-way ANOVA and post hoc Tukey tests (p< 0.05). RESULTS: There were statistically significant differences between bond strength values of group 1 (ASB) and group 2 (H+ASB) (p< 0.001) and group 1 (ASB) and group 3 (H+CHX+ASB) (p< 0.001). Similarly, significant differences were seen between group 4 (CSB) and group 5 (H+CSB) (p< 0.001) and between group 4 (CSB) and group 6 (H+CHX+CSB) (p< 0.001). CONCLUSION: Contamination with hemostatic agent reduced the SBS of both total- and self-etching adhesive systems. In addition, application of chlorhexidine after the removal of hemostatic agent had a negative effect on SBS of total- and self-etching adhesive systems.