Effect of filler and application mode on micro-shear bond strength of etch-and-rinse adhesive systems

AbstractObjectiveTo evaluate the effect of the application modes and the presence of filler of etch-and-rinse adhesive systems on the micro-shear bond strength test (μSBS) to bovine dentin.MethodsTwenty bovine teeth had the enamel removed and dentin surface exposed. Dentin was etched with 37% phosphoric acid and the following adhesive systems were applied: One Step and One Step Plus with two modes (no rubbing action and vigorous rubbing action). To each tooth six Tygon cylinders with internal 0.76mm were filled with flowable composite resin. All cylinders were light polymerized for 40s (Optilux 501). The μSBS was performed in a universal testing machine (Instron 5565), with specimens held in place by a wire (0.2mm) loop, and force loaded to failure. The fracture mode was evaluated. The results in MPa were statistically analyzed by two-way ANOVA and Holm–Sidak tests (α=0.05).ResultsThe two-way ANOVA detected no interactions between factors (p=0.865), but only differences between the adhesive systems (p=0.042) and application modes (p=0.014). One Step Plus obtained a higher μSBS than One Step, and vigorous application increased bond strength of adhesives systems. The predominant failure modes of all groups were adhesive-mixed.ConclusionThe adhesive systems showed the best μSBS results with presence of filler and active mode application