Influence of Duration of Blood Contamination on Adhesion of 4-META/MMA-TBB Resin to Root Dentin

Abstract

Purpose: We have previously reported the influence of blood contamination on adhesion of 4-META/MMA-TBB resin to dentin. Our results showed that blood contamination after surface treatment with an aqueous solution of 10% citric acid and 3% ferric chloride (10-3 solution) significantly decreased the adhesion, even if the blood was washed away. If contaminated, it was recommended that the surface be retreated with 10-3 solution and rinsed with water. Therefore, we concluded that blood coagulation inhibits adhesion. In the present study, we evaluated the influence of duration of blood contamination after surface treatment on the leakage and bond strength of 4-META/MMA-TBB resin to dentin. Methods: Bovine root dentin surfaces were contaminated with blood for 2, 5 and 15 seconds after dentin surface treatment with 10-3 solution. The contaminated surface was then rinsed with water (15 seconds), air-dried, or retreated with 10-3 solution (5 seconds). The dye leakage test, microtensile bond strength (MTBS) test, and SEM observation were employed to evaluate the leakage and bond strength of 4-META/MMA-TBB resin to dentin. Results: Results showed that leakage increased and MTBS decreased with an increase in the duration of blood contamination after surface treatment. This is due to the difficulty of removing blood contaminants by simple rinsing as coagulation progresses. However, the leakage value and MTBS were similar to those of the uncontaminated group on re-treatment with 10-3 solution. This may be due to the decalcifying ability and anticoagulant action of citric acid in 10-3 solution, which might effectively remove the blood components. Conclusion: It is recommended that the contaminated surface be thoroughly rinsed with water and re-treated with 10-3 solution, regardless of the duration of blood contamination in the process of adhesion of 4-META/MMA-TBB resin to dentin.