LAUSR

Background Nowadays, the universal adhesive become more popular among clinicians due to its simple procedure. The application of universal adhesive on root canal dentin prior the self-adhesive resin cement may increase bond-strength between fiber post and dentin. The objective of this study was to evaluate the effect of different etching modes (etch-and-rinse and self-etch) to universal adhesives on push-out bond strength of fiber post. Material and Methods Thirty extracted sound human lower premolars were randomly divided into three groups based on adhesives systems prior to fiber post cementation; two-step etch-and-rinse (group A, Adper Scotchbond), etch-and-rinse universal (group B, Prime & Bond Universal), and self-etch universal (group C, Prime & Bond Universal). After adhesive application, self-adhesive resin cement was filled to the prepared root canal (Smart CEM2, Dentsply) for fiber post cementation. The adhesion between the fiber post and root canal walls was investigated using push-out test after 24 h water storage at 37◦C and the modes of failure were determined under SEM. Data were analyzed using two-way ANOVA test and the Bonferroni test was used to compare values among the three adhesives groups, followed by Tukey HSD for multiple comparisons. Furthermore, Weibull parameters were calculated for tested groups. Results Universal adhesive with self-etch mode significantly improved bond-strength compared to the two-step etch-and-rinse group (p<0.05). The coronal part has higher bond strength than the apical section (p<0.05). However, the bond-strength in two-step etch-and-rinse and etch-and-rinse universal was not significantly different. Self-etch mode showed higher bond strength compared to etch-and-rinse universal adhesive in the apical root section (p<0.05). SEM revealed that all tested groups predominantly had an adhesive failure (p>0.05). Conclusions Self-etch mode in universal adhesive system were effectively improved the push-out bond strength of fiber post to root canal dentin, especially in apical root section. Key words:Push-out bond-strength, self-adhesive resin cement, self-etch adhesive, total-etch.