Effect of human, dentin, albumin and lipopolysaccharide on the antibacteerial activity of endodontic activity of endodontic irrigants

Abstract

Context: Human dentin powder (HD), bovine serum albumin (BSA) and endotoxin (LPS) may affect the antimicrobial activity of irrigating solutions. Aim: To evaluate the inhibitory effect of HD powder, BSA, and LPS on the antibacterial activity of 0.5%, 1%, 2.5% and 5% sodium hypochlorite (NaOCl), 2% chlorhexidine (CHX) gel, BioPure mixture of tetracycline, citric acid, and detergent (MTAD), and QMix. Methods: The direct contact test against Enterococcus faecalis (ATCC 29212)for 2-min, 30-min and 6-h was used. Sterile pyrogen-free water was the negative control. After experimental periods, a neutralizing agent was used. Colony-forming units were determined by 10-fold serial dilutions and culture on agar plates. Data were analyzed by Kruskal-Wallis and Dunn's test (a = 5%). Results: In the absence of inhibitors, all irrigants eliminated E. faecalis. In contact with HD, all solutions eliminated E. faecalis within 2-min, with the exceptionof MTAD. In the presence of BSA, only 5% NaOCl killed E. faecalis within 2-min. LPS did not affect the antibacterial effect of any irrigant. At 30-min an at 6-h, all substances eliminated E. faecalis. Conclusions: In the presence of albumin, irrigants needed >2-min to eliminated E. faecalis, except for 5%NaOCl. The same was observed in the presence of dentin when E. faecalis was exposed to MTAD.