Shear bond strength of universal adhesive systems to a bioactive dentin substitute (Biodentine®) at different time intervals

Aim: The aim of this study was to compare the shear bond strength (SBS) of various adhesive systems to a bioactive dentin substitute Biodentine® with different time intervals. Methods: Three hundred and fifty cylindrical acrylic blocks with a hole (4 mm diameter and 2 mm height) were prepared. The holes were filled with Biodentine®, and the specimens were allocated into 5 main groups according to waiting times (group 1, 12 min; group 2, 24 h; group 3, 48 h; group 4, 72 h; and group 5, 96 h). All specimens were stored at 37 °C with 100% humidity during the waiting time. Then each group was divided into 7 subgroups of 10 units each: subgroup 1, Prime&Bond NTTM; subgroup 2, Single Bond Universal (self-etch mode); subgroup 3, Single Bond Universal (etch and rinse mode); subgroup 4, All-Bond UniversalTM (self-etch mode); subgroup 5, All-Bond UniversalTM (etch and rinse mode); subgroup 6, G-aenial Universal BondTM (self-etch mode); and subgroup 7, G-aenial Universal BondTM (etch-and-rinse mode). After the application of adhesive systems, compomer Dyract XP Bond® was applied over Biodentine® SBSs were measured using a universal testing machine. After the SBS test, the fractured surfaces were examined under a stereomicroscope at 25× magnification, and the data were analyzed with Kruskal-Wallis and Mann-Whitney U (with Bonferroni correction) tests. Results: Biodentine® exhibits lower shear bond strength values in the 12 min groups. No significant differences were observed between self-etch or etch-and-rinse bonding modes. Conclusion: A 24-h waiting period after the mixing of Biodentine® could be useful to obtain higher SBS measurements. Also, similar SBS values were observed for the universal adhesives regardless of application mode.