Sodium chloride and potassium sorbate: a synergistic combination against Enterococcus faecalis biofilms: an in vitro study

• Published in: European journal of oral sciences Vol. 120; no. 5; pp. 452 - 457
• Main Authors: van der Waal, Suzette V., Jiang, Lei-Meng, de Soet, Johannes J., van der Sluis, Lucas W.M., Wesselink, Paul R., Crielaard, Wim
• Format: Journal Article
• Language: English
• Published: England Blackwell Publishing Ltd 01-10-2012
• Subjects: Anti-Infective Agents, Local - pharmacology; Biofilms - drug effects; Calcium Hydroxide - pharmacology; Chlorhexidine - pharmacology; Colony Count, Microbial; Dentistry; disinfection; Drug Combinations; endodontic; Enterococcus faecalis; Enterococcus faecalis - drug effects; hyperosmosis; Indexing in process; potassium sorbate; Root Canal Irrigants - pharmacology; Sodium Chloride - pharmacology; Sorbic Acid - pharmacology
• ISSN: 0909-8836; 1600-0722
• DOI: 10.1111/j.1600-0722.2012.00982.x

Incomplete disinfection of the root canal system is a major cause of post‐treatment disease. This study aimed to investigate the disinfecting property of organic acid salts and sodium chloride (NaCl), in a double‐hurdle strategy, on Enterococcus faecalis biofilms. First of all, the high‐throughput resazurin metabolism assay (RMA) was used to test a range of organic acid salts. Then, to gain more insight into the efficacy of sorbate salt solutions, 48‐h E. faecalis biofilms were evaluated in colony‐forming unit (CFU) assays. Chlorhexidine (CHX) and calcium hydroxide [Ca(OH)2] were tested in parallel as controls. Sorbate salt produced the largest and most significant reduction of fluorescence intensity in the RMA assay. Neither NaCl nor potassium sorbate (KS) alone induced a clinically relevant reduction of CFU counts after 1 h. Surprisingly, the combination of the two in a single solution had a synergistic effect on the inactivation of E. faecalis. Potassium sorbate amplified the efficacy of NaCl. Of the salts tested, NaCl with KS eradicated E. faecalis biofilms within 1 h. This study showed that the double‐hurdle strategy indeed leads to synergistic efficacy and is a possible next step in the complete disinfection of endodontic infections.