Effects of cavity disinfectants on bond strength of an etch-and-rinse adhesive to water- or ethanol-saturated sound and caries-affected dentin

Objective: To evaluate the effect of cavity disinfectants on the immediate microtensile bond strength (TBS) of an etch-and-rinse adhesive to water- and ethanol-saturated sound and caries-affected dentin (CAD). Material and Methods: Thirty-six human molars were sectioned to expose 1/3 of the mid-coronal dentin surface. Sound (n=18) and CAD (n=18) specimens were divided into six groups each (n=3): one positive control (sound), one negative control (CAD), and five experimental groups each. In the control group, dentin surfaces were bonded using an etch-and-rinse adhesive with a traditional water-wet bonding technique. In the experimental groups, ozone was applied before etching and chlorhexidine after etching. In the ethanol-wet bonding groups, acid-etched dentin surfaces were treated with ethanol. Following adhesive application and composite buildups, bonded specimens were sectioned to form sticks. Failure modes were analyzed using a stereomicroscope. Results: The water-wet bonded sound control group yielded the highest TBS among all groups (p<0.001). The lowest TBS values were observed in the ozone groups (p<0.05). The ethanol-wet bonded CAD group exhibited a higher TBS than the water-wet bonded negative controls. Although compared to the positive control, chlorhexidine decreased the TBS (p<0.05), an increase with no significant difference was observed in the negative control (p>0.05). Conclusions: The TBS values of CAD were lower than those of sound dentin. Ethanol-wet bonding improved the TBS of CAD. Ozone application reduced the TBS in both sound and CAD; chlorhexidine improved the immediate TBS after etching in CAD.