Effect of 2% chlorhexidine gluconate on the degradation of resin composite–dentin bond strength when using self-etch adhesive systems

Objective: The purpose of this study was to analyze the effect of 2% chlorhexidine gluconate (CHX) on the degradation of composite resin–dentin bond strength when using self-etch adhesive systems. Methods: CHX (2%) was applied before application of two-step self-etch (TSC) and one-step self-etch (OSC) adhesive. Resin composite was applied incrementally. Specimens from the degradation treatment group were immersed in 10% NaOCl for 1 h. Shear bond strength was tested with a universal testing machine and analyzed using one-way ANOVA and Dunnett’s T3 post-hoc test. The composite resin–dentin bonds were observed using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Results: In the treatment group without 10% NaOCl, shear bond strength values were higher in the 2% CHX-treated group (TSC 11.67±1.76 MPa and OSC 10.19±1.44 MPa) than in the untreated group (TSC 10.93±1.31MPa and OSC 9.97±1.41 MPa), although this difference was not statistically significant. In samples exposed to10% NaOCl, shear bond strength values were higher in the 2% CHX-treated group (TSC 11.14±1.22 MPa and OSC 9.95±1.21 MPa) than in the untreated group (TSC 10.08±0.45 MPa and OSC 8.62±0.85 MPa), although this difference was not statistically significant. The SEM of samples from the 2% CHX-treated group showed less degradation than samples from the untreated group did. Conclusion: Application of 2% CHX may decrease the degradation of the resin composite-dentin bond.