Microtensile Dentin Bond Strength of Bioactive-Vitroceramics Incorporated Into Adhesive Systems

Objectives: To evaluate the influence of different concentrations of vitreous ceramic particles (Biosilicate^®) on dentin bond strength (DBS) of experimental self-etch and etch-and-rinse adhesive systems.
Methods: Forty sound human molars were cut in quarters and flattened. Standardized smear layer on the exposed dentin surfaces was achieved with 600-grit silicon carbide paper and water. The quarters of the same tooth (n=20) were treated with different percentages (0% - control; 2% and 5% - by weight) of Biosilicate^®, incorporated into two experimental adhesive systems: Exp-1 (total etch, 2 steps) and Exp-2 (self-etching, 2 steps) that were compared with the respective commercial adhesive system (Single Bond, 3M ESPE and AdheSE, Ivoclar Vivadent). The adhesive systems were applied and light-cured for 10 seconds. A composite resin (Z350, 3M ESPE) block (6 mm high) was built up 3 increments on the dentin surface. Each layer was light-cured for 20 seconds. The quarters were sectioned (Isomet 1000, Buehler) perpendicular to the bond surface (0.9x0.9mm), and the beams were randomly separated into two aging groups: Immediate or 6 months distilled/deionized water (37°C). The microtensile DBS was tested (0.5mm/s). The failure type of the beams was examined by stereomicroscope and TEM. Data were statistically analyzed (2-way ANOVA, Bonferroni, p<0.05).
Results: The Exp-2 self-etch adhesive presented higher DBS than Exp-1 etch-and-rinse, different (p<.05) from all other groups, except (p>.05) for 5% of the Biosilicate^® group. Commercial and Exp-1 adhesives presented similar results (p>.05) regardless the percentage of Biosilicate^® added. There was no difference between immediate and 6 months groups, irrespective the concentration of the Biosilicate^®.
Conclusions: The addition of Biosilicate^® particles is not feasible for the etch-and-rinse adhesive system. For self-etch adhesive, the addition of 2% of Biosilicate^® does not cause adverse effects on the material’s properties.