Microtensile bond strength of composite resin and glass ionomer cement with total-etching or self-etching universal adhesive

Abstract

PurposeTo assess the effect of acid etching (AE) and adhesive systems on the microtensile bond strength of conventional glass ionomer cement (GIC) and a nanofilled composite resin. Materials and methodsSpecimens of conventional GIC (RIVA, Self-cure, SDI) were prepared in a bipartite Teflon mold and randomly assigned (n=12) to G1- GIC+Single Bond 2 (SB2) (3M-ESPE); G2- GIC+Acid etching (AE) (37% phosphoric acid, Condac, FGM) + SB2; G3- GIC+Single Bond Universal (SBU) (3M-ESPE); and G4- GIC+AE+SBU. The adhesive systems and the composite (Filtek Z350XT, 3M-ESPE) were inserted into the mold. After 7 days stored in a humid environment, the specimens were sectioned into five slices (Isomet 1000, Buehler). Hourglass slices were trimmed and subjected to microtensile bond strength testing (BISCO®; Schaumburg, USA) with 0.5mm/min crosshead speed. Data were analyzed by two-way ANOVA and the Tukey test (SPSS 17.0, α=5%). ResultsThe microtensile bond strength (MPa) means (standard deviation) were G1=9.46(3.79), G2=6.27(3.21), G3=9.35(3.91), and G4=10.13(3.53). G2 differed significantly from the other groups (p<0.001). G1, G3 and G4 were not significantly different from each other (p>0.05). There were 83% mixed fractures, 9.5% cohesive and 7.5% adhesive. ConclusionGIC etching promoted higher microtensile bond strength with universal adhesive than with a total-etch adhesive system. Acid etching is not necessary to enhance the universal adhesive bond strength and negatively affected the bond strength of the total-etch adhesive system. Without etching the GIC, there is no difference in microtensile bond strength between the adhesive systems.