Aging Effect on Push-Out Bond Strength of Six Resin Cements: An In Vitro Study

The number of resin cements marketed for fiber post cementation has increased significantly. This study compared the push-out bond strength (PBS) of self-adhesive and universal resin cements used to lute fiber posts at 24 h and after 6 months of aging in artificial saliva. Fiber posts were luted to eighty human roots endodontically treated with four self-adhesive/one-step resin cements, with one of them also used in combination with its appropriate tooth primer; one universal resin cement, applied as one-step or together with its corresponding universal adhesive (multi-step); and one adhesive/multi-step resin cement, as a control. After storage (24 h or 6 months), the interfaces were subjected to PBS tests and the data were analyzed by two-way ANOVA and Tukey and Student's t-tests (p < 0.05 defined as statistical significance). The results showed that Scotchbond Universal Plus + RelyX Universal attained statistically higher values at 24 h and 6 months. At 24 h, all resin cements yielded similar PBS to root dentin, while at 6 months, NormoCem obtained the lowest PBS. Storage for 6 months significantly decreased PBS for NormoCem and Multilink Automix. Root section did not influence PBS regardless of storage time. It was concluded that PBS is resin cement dependent. The universal resin cement, RelyX Universal, applied in combination with Scotchbond Universal Plus adhesive, obtained a higher and more stable PBS than the other resin cements tested.