Bonding potential to dentin of one-component self-etch adhesives

Objectives: The purpose of the study was to assess the bonding potential to dentin of newly introduced all-in-one adhesives.

Methods: The one-component adhesives AdheSE One (Ivoclar-Vivadent, ASO), Bond Force (Tokuyama, BF), and Xeno V (Dentsply, XV) were tested in comparison with the etch-and-rinse adhesive Prime&Bond NT (Dentsply, PBNT), that was considered as control. The bond strength to middle dentin was measured with the microtensile technique. On three extracted molars per group a middle dentin substrate was exposed by cutting with a water cooled diamond blade. Then, a clinically relevant smear layer was created by grinding with a wet 600-grit SiC paper and the bonding procedure was performed according to the manufacturers instructions. Microtensile beams were obtained following the non-trimming variant of the technique. The bond strengths in MPa were statistically analyzed including the pre-test failures as ‘zero' values (Kolmogorov- Smirnov test, Levene test, One-Way Analysis of Variance, Tukey test; p<0.05). Two extracted molars per group were used for scanning electron microscope observations of the ultrastructural characteristics of the dentin-adhesive interface.

Results: The following bond strengths were recorded in MPa (mean±standard deviation): ASO 33.3±21.6; BF 40.2±17.9; XV 45.9±26.1; PBNT 38±25.5.

Conclusion: The statistical analysis demonstrated that BF and XV achieved a bond strength comparable to that of the control etch-and-rinse adhesive PBNT, whereas ASO measured a significantly lower bond strength than PBNT. With regard to microscopic characteristics, the all-in-one adhesives were able to infiltrate the smear layer and penetrate the dentin tubules to a limited depth, thus forming short and thin resin tags. Resin tags were more diffuse and deeply penetrating following the use of the etch-and-rinse adhesive PBNT.