Influence of methods of application of self-etching adhesive systems on adhesive bond strength to enamel.

Purpose: To assess the influence of variations in the application technique of self-etching adhesive systems on the adhesive bond strength to enamel.
Materials and Methods: One hundred thirty bovine teeth were used and divided into 13 groups. The teeth were embedded in acrylic resin, ground until a flat enamel area was exposed, and polished with 600-grit abrasive paper. The self-etching adhesive systems One Up Bond F, Clearfil SE Bond, Self & Etch were used, and the conventional adhesive Magic Bond and acid etching were used as the control group. One or two layers of the self-etching systems were actively or passively applied. Composite cylinders were made over the bonding area. The samples were submitted to shear bond testing at a speed of 1 mm/min. Statistical analysis of the data was performed using two-way ANOVA, followed by Tukey's test at a 5% level of significance.
Results: Significant variations were observed for the factors type of adhesive (p = 0.001, F = 193,3594, df = 3) and application technique (p = 0.001, F = 29,9119, df = 1). No significant interaction was found between the two factors (p = 0.08). The adhesives Clearfil SE Bond and One Up Bond F presented significantly higher adhesive bond strength means than Self & Etch. The active application of two layers resulted in higher bond strength means than the other techniques.
Conclusion: The application technique had a significant influence on adhesive bond strength to enamel.