[Influence of EDC ethanol solution on dentin shear bond strength with a self-etch adhesive system]

To evaluate the bonding ability of one representative self-etch adhesive system by applying the micro-shear bond strength test method with different concentrations of carbodiimide [1-ethyl-3-(3-dimethylaminopropyl) carbodiimide, EDC] ethanol solution pretreatment.

Extracted sound human third molars were collected from patients ranging 18 to 40 years. In the study, 80 molars were first sectioned to prepare a flat middle coronal dentin surface and then were randomly divided into 5 groups (n=16) according to without/with different surface treatments [blank control; 80% (volume fraction) ethanol control; EDC ethanol solution of three concentrations (0.01 mol/L, 0.3 mol/L and 0.5 mol/L)]. Each specimen underwent a micro-shear bond strength test and failure mode observation. The data collected were subjected to statistical analysis using one-way ANOVA and post hoc Tukey's test to analyze the difference of the micro-shear bond strength, and chi-square test/Fisher's exact test for the failure mode frequency of the micro-shear bond strength test specimens at a significance level of P=0.05.

The micro-shear bond strength of the three concentration EDC treatments were (35.29±8.97) MPa (0.01 mol/L EDC treatment group), (40.24±9.68) MPa (0.3 mol/L EDC treatment group), (37.38±9.66) MPa (0.5 mol/L EDC treatment group) separately; and that of the 80% ethanol group was (37.49±7.76) MPa. All micro-shear bond strength value of the above four groups was statistically higher than that of the blank control group [(33.81±7.98) MPa]. The immediate micro-shear bond strength and failure mode was of no statistically significant difference among all the groups. It was noticed that the immediate micro-shear bond strength of 0.3 mol/L was higher than that of all the other groups, especially higher than that of the 80% ethanol pretreatment group despite that there was no significant difference among all the groups. And the test of failure mode indicated that the cohesive failure was more common, while the frequency of adhesive failure was rare in each experimental group.

EDC pretreatment had no adverse effect on the immediate micro-shear bond strengths of Clearfil SE Bond. Meanwhile, EDC treatment did not cause more adhesive failure in immediate micro-shear test, which had further denoted what was said above. However, it needs more research to illustrate the anti-enzymatic role of EDC in dentin bonding.