The durability of the resin-dentin interface in the oral environment is an important concern in bonded restorations. This study aimed to evaluate and compare the effect of incorporation of tricalcium silicate (TCS) to a universal adhesive on microtensile bond strength (µTBS) to dentin. Moreover, this study was designed to evaluate micromorphological patterns of tooth/restoration interface, immediately after 24 h and after 6 months storage. Forty permanent human molars were selected and randomly assigned into two equal groups (n = 20) according to the incorporation of TCS to the universal adhesive; Group1: Control group without incorporation of TCS. Group2: with the incorporation of TCS to the universal adhesive. Each group was further subdivided into immediate and delayed testing subgroups according to the testing time. The adhesives were applied according to the manufacturers’ instructions. Composite/dentin beams were prepared (1 mm2). The samples were subjected to µTBS testing. Three restored specimens from each group were utilized in micromorphological evaluation of resin-dentin interfaces using Scanning Electron Microscope (SEM). µTBS data were statistically analyzed using two-way ANOVA and multiple comparison post hoc tests. The outcome of Two-way ANOVA for the µTBS test revealed that both the incorporation of TCS and time had statistically significant differences in the µTBS (p 0.05). Nonetheless, µTBS significantly declined in the delayed control group. Additionally, all tested groups had a statistically significant difference when compared to the delayed control adhesive group (p < 0.05). The hybrid layers made with both modified and unmodified universal adhesive demonstrated the penetration of resin tags except for the immediate TCS group. It has been concluded that incorporation of TCS into universal adhesive seems to improve the bond strength to dentin. Six months aging has no adverse effect on bond strength of TCS incorporated universal adhesive to dentin.
Zayed et al. (Thu,) studied this question.