Bottom/top hardness ratio and dentin bonding stability of conventional and bulk-fill resin composites

Aim: To evaluate the bottom/top hardness ratio (B/T) and dentin bonding stability of conventional bulk-fill resin composites in high c-factor preparations. Methods: Regular (Tetric N-Ceram – TNC, Polofil Supra PFS), regular Bulk fill TBF, Admira Fusion X-tra AFX), low viscosity N-flow TNF, Base XTB) were used to restore 180 conical The specimens randomly distributed 12 groups (n = 15) according storage time-points (24 h six months) tested. After 24 storage, all subjected analysis. Then, push-out bond strength test was performed half other maintained for months on water before testing. failure modes analyzed a stereomicroscopic. data statistically using one- two-way ANOVA Tukey post-test (p <0.05). Results: There no significant differences among (p>0.05). Regardless timepoint, showed highest values (p<0.05). Only lower at six-month Adhesive failures more predominant low-viscosity composites. Conclusion: Although DoC not affected by different materials tested, only did present loss after storage.