Methods: Thirty freshly extracted human teeth were sectioned longitudinal to expose superficial dentin and dentin substrates were polished with 600 grit SiC paper. The materials tested were: two self-adhering flowable resins, Fusio Liquid Dentin (Pentron Clinical) and Vertise Flow (Kerr) and a self-etch adhesive/flowable resin, S3 Bond/Clearfil Majesty Flow (Kuraray). Manufacturers' instructions for applying of materials were strictly followed. A cylindrical teflon mould (3x4mm) was placed over the dentin substrate and filled with each of the tested materials. Ten specimens were prepared for each material and all specimens were stored in distilled water at 370 C for 24 hours. SBS was measured using a universal testing machine at a rate of 0.5mm minˉ until failure. The load to fracture was calculated in MPa and mean data were statistically analyzed with the Welch robust analysis of variance and Games-Howell statistic at p<0.05. Failure patterns were analyzed using a stereomicroscope x40 in order to determine the failure modes. Representative specimens were evaluated under SEM at various magnifications. Results: No statistically significant differences (p>0.05) were found between the two self-adhering materials. Significant higher SBS values were observed with the self-etch adhesive/flowable resin (Welch statistic p<0.001) in comparison to the self-adhering flowables. Stereoscopic evaluation of the failure patterns showed that failures of the self-adhering systems were exclusively adhesive, while the failure patterns of the self-etch adhesive/flowable resin were mixed types of failure. SEM findings confirmed the results.
Conclusion: SBS of the self-adhering flowable resins to dentin substrates was lower than the flowable resin and its bonding agent tested.