Method: 96 human molars were divided into 12 groups (n=8). The occlusal surfaces of the teeth were sectioned in order to expose flat dentin surface. The teeth were then divided according to the treatment of the conditioned dentin: dentin saturated with water, dentin saturated with aqueous solution of chlorhexidine, dentin saturated with ethanol and dentin saturated with chlorhexidine ethanol solution. The solution was applied after acid etching procedure (35% phosphoric acid). The adhesive systems used were: Adper Single 2 (3M ESPE, St. Paul, MN, EUA), Prime&Bond 2.1 (Dentsply, Milford, DE, EUA) and Excite (Ivoclar Vivadent, Schaan, Liechtenstein ). After the adhesive procedure, three horizontal increments of composite resin (Filtek Z250 - 3M ESPE) with 1mm of thickness each one were applied on the adhesive surface. After photopolymerization, the teeth were stored during 7 days in artificial saliva at 37° Celsius. After the storage period, teeth were sectioned perpendicular to the bonding surface, obtaining stick-shaped specimens with cross-sectional area of 0.81 mm2. The specimens were submitted to the microtensile test at 0.5 mm/min. Data were analyzed with ANOVA and Tukey's test (p < 0.05).
Result: It was observed that Prime&Bond 2.1 and Excite shown a statistically significant increase on the bond strength when the conditioned dentin was treated with ethanol mixed or not with chlorhexidine
Conclusion: The use of ethanol–wet bonding with or without chlohexidine seems to be an interesting approach when combined with two-step etch-and-rinse adhesive systems.