bond strength of composite resin to enamel: assessment of two ethanol wet-bonding techniques.

ethanol wet-bonding (ewb) technique has been stated to decrease degradation of resin-dentin bond. this study evaluated the effect of two ewb techniques on composite resin-to-enamel bond strength.silicon carbide papers were used to produce flat enamel surfaces on the buccal faces of forty-five molars. optibond fl (ofl) adhesive was applied on enamel surfaces in three groups of 15 namely: enamel surface and ofl (control);protocol 1 of the ewb technique: absolute ethanol was applied to water-saturated acid-etched enamel surfaces for 1 minute before the application of ethanol-solvated hydrophobic adhesive resin of ofl 3 times;protocol 2: progressive ethanol replacement; water was gradually removed from the enamel matrix using ascending ethanol concentrations before ofl application. composite build-ups were made and the specimens were stored for 24 hours at 37°c and 100% relative humidity. shear bond strength test was performed using a universal testing machine at 1 mm/min crosshead speed. fracture patterns were evaluated microscopically. data were analyzed with one-way anova and fisher's exact test (α=0.05).there were no significant differences in bond strength between the groups (p=0.73). however, regarding failure patterns, the highest cohesive enamel fractures were recorded in groups 2 and 3.in this study, although both methods of ewb did not influence immediate bond strength of composite resin to enamel, the majority of failure patterns occurred cohesively in enamel.