Influence of Dentinal Moisture on the Properties of Universal Adhesives

Objectives: The aim of this study was to evaluate the microtensile bond strength (μTBS), degree of conversion (DC), and silver nitrate deposition (NL) of three universal adhesive systems, used in etch-and-rinse and self-etch modes, on wet and oversaturated dentin surfaces.

Methods: Human molars were assigned to 12 groups by: Universal adhesive systems: (Ambar Universal APS [AMB]; Prime & Bond Active [PBA]; Scotchbond Universal Adhesive [SBU]; Adhesive strategies: (etch-and-rinse [ER] or self-etch [SE]); and Degree of surface moisture: (wet or oversaturated dentin surface). After restoration, the specimens were sectioned into resin-dentin beams and tested for μTBS, DC, and NL. A three-way ANOVA and Tukey’s test were used for statistical analysis (5%).
Results: No significant difference was observed in μTBS (p > 0.14) and DC (p > 0.67) among the tested adhesives regardless of the adhesive strategy employed when dentin was kept wet. AMB (ER and SE) resulted in a higher mean μTBS and DC values when the dentin was kept oversaturated (p < 0.001). A significant decrease of μTBS (p < 0.0001) and DC values (p < 0.001) were observed for PBA (ER) and SBU (ER and SE) when dentin was oversaturated. For ER and SE, SBU showed a significant increase in NL values in oversaturated dentin compared to those of wet dentin (p < 0.001).
Conclusions: Universal adhesives systems showed good adhesive performance to dentin when dentin was kept wet. However, in oversaturated dentin, the response is material dependent.