Purpose
: The aim of the study was to evaluate the effect of addition of 20% bioactive glass nanoparticles (bioglass) to a universal adhesive on its microtensile bond strength to enamel etched for different times.
Methods: Twenty eight enamel central incisor specimens were used in this study and divided into four groups; E1, E2, E3 and E4. E1and E3 were bonded using unmodified universal adhesive while E2 and E4 were bonded using 20% bioglass modified adhesive. Groups E1 and E2 were etched with 37% phosphoric acid for 30 seconds while E3 and E4 were etched for 6o seconds. Adhesive was applied to the enamel surface using a microbrush. Adhesive was left undisturbed on the enamel surface for 20 seconds for group 1and 2 or 30 seconds for gp 3 and 4 before curing. Composite resin was built up and the specimens were subjected to microtensile bond strength testing.
Results: Data was analyzed using T-test and one-way ANOVA. Results showed that bond strength values were statistically similar for both modified and unmodified adhesives. Thirty seconds etching time produced significantly higher bond strengths than sixty seconds etching for either adhesive.
Conclusions: Within limitations of this study, it can be concluded that bioglass incorporation into the universal adhesive has no deleterious effect on bonding to enamel. Increasing the etching time is not recommended as it causes a loss of bond strength.