In vitro evaluation of bonding effectiveness to dentin of all-in-one adhesives

The study was aimed at assessing the bonding potential of all-in-one adhesives to dentin.

The microtensile bond strength of the all-in-one adhesives Bond Force (Tokuyama), AdheSE One (Ivoclar-Vivadent), and Xeno V (Dentsply) was measured in comparison with the etch-and-rinse system XP Bond (Dentsply). The ultrastructural characteristics of dentin-adhesive interface were observed under scanning electron microscope (SEM). Twenty human extracted third molars had their mid-coronal dentin exposed and ground with wet 600-grit SiC paper in order to create a standardized smear layer. Bonding procedures were performed according to the manufacturers' instructions and microtensile beams were obtained with the "non-trimming" technique. The bond strengths in MPa were statistically analyzed including pre-test failures as "zero" values (Kolmogorov-Smirnov test, Levene's test, One-Way ANOVA, Tukey's test p<0.05).

The following bond strengths were recorded in MPa (mean+/-standard deviation): AdheSE One 31.7+/-21.3; Xeno V 42.8+/-26.4; Bond Force 43.3+/-22.1; XP Bond 51.9+/-18.6. The statistical analysis demonstrated that the bond strengths achieved by Bond Force and Xeno V were similar to that of the etch-and-rinse adhesive, whereas the bond strength of AdheSE One was significantly lower. A distinct hybrid layer with resin tags was seen only in XP Bond specimens. All-in-one adhesives demonstrated a rather superficial interaction with the dentin substrate.

Although the strongest bond to dentin was established by the etch-and-rinse system, however the all-in-one adhesives containing organic solvents reached bond strength levels that were comparable from a statistical point of view.