Influence of cariogenic challenge on bond strength stability of dentin

The aim of this study was to evaluate the effect of cariogenic challenge on the microtensile bond strength values (μTBS) of dentin pre-treated with chlorhexidine digluconate (CHX) or sodium hypochlorite (NaOCl). Thirty-six sound molars were selected and randomly assigned to 3 dentin pre-treatments (distilled water - control, 2% CHX and 10% NaOCl) and 4 aging protocols (24h control, biofilm without cariogenic challenge, biofilm with cariogenic challenge, and 18-month water storage). The same etch-and-rinse adhesive system and composite resin were used for all groups (n=30 beams). For the biofilm groups, dental microcosm biofilms originated from saliva of a healthy donor were grown on the samples with a defined medium enriched with mucin, with or without 10% sucrose, according to the group. After the experimental period, the microtensile test was performed. Data were analyzed with ANOVA followed by Tukey test (p<0.05). The pre-treatment did not influence μTBS for all aging conditions (p=0.188), but the type of aging affected the bond strength (p<0.001). Cariogenic challenge and water storage aging affected the bond stability resulting in a decrease of the μTBS, but the pre-treatments did not influence the μTBS.