Effect of blood contamination with 2-step self-etching adhesives

Objectives: The purpose of this study was to evaluate the effect of blood contamination with 2-step self-etching adhesives on microtensile bond strength to dentin.

Materials & Methods: Three commercially available 2-step self-etching adhesives (Clearfil SE bond, AdheSE, Tyrian) and 1 resin composite (Filtek Z-250) were used. Molars that had been stored in distilled water with 0.5% thymol were ground #600 SiC paper under running water to produce a standardized smear layer. The specimens were randomly divided into groups according to the three adhesive systems. The adhesive systmens were used under five conditions: no contamination, which was the control(C); contamination of the primer treated surface with blood, then drying and re-application (Contamination 1); contamination of the primer treated surface with blood, then washing, drying and reapplication (Contamination 2); contamination of primer treated, light-cured adhesive surface with blood , then drying and re-application (Contamination 3); contamination of primer treated, light-cured adhesive surface with blood, then washing, drying and reapplication (Contamination 4). Following igt curing of the adhesive, the resin composite was placed in 3 increments up to a 5 mm-thick layer on the bonded surface. All specimes were stored in distilled water at 37°C for 24 hours. The microtensile bond strength was measured using a universal testing machine and data was analyzed by two-way ANOVA followed by the Duncan test to make comparisons among the groups (p=0.05).

Results: Two-way ANOVA showed that the factors ‘surface treatments' and ‘materials; and their interaction were significant (p< 0.05). Except Tyrian group, contamination groups showed lower bond strength than the control. There were no statistically significant difference among the control groups except tyrian group.

Conclusions: Blood contamination negatively affected the microtensile bond strength of 2-step self-etching adhesive systems to dentin. Neither of the decontamination methods used in this study reversed the harmful effect of blood contamination.