title: Sodium chloride and potassium sorbate: a synergistic combination against Enterococcus faecalis biofilms: an in vitro study.
abstract: 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.
authors.affiliation: Department of Conservative & Preventive Dentistry, Academic Centre for Dentistry Amsterdam (ACTA), Amsterdam, the Netherlands. s.vd.waal@acta.nl
authors.forename: Suzette V
authors.initials: SV
authors.lastname: van der Waal
authors.forename: Lei-Meng
authors.initials: LM
authors.lastname: Jiang
authors.forename: Johannes J
authors.initials: JJ
authors.lastname: de Soet
authors.forename: Lucas W M
authors.initials: LW
authors.lastname: van der Sluis
authors.forename: Paul R
authors.initials: PR
authors.lastname: Wesselink
authors.forename: Wim
authors.initials: W
authors.lastname: Crielaard
mesh_terms: D000891:Anti-Infective Agents, Local / Q000494:pharmacology*; D018441:Biofilms / Q000187:drug effects; D002126:Calcium Hydroxide / Q000494:pharmacology; D002710:Chlorhexidine / Q000494:pharmacology; D015169:Colony Count, Microbial; D004338:Drug Combinations; D013293:Enterococcus faecalis / Q000187:drug effects*; D012388:Root Canal Irrigants / Q000494:pharmacology; D012965:Sodium Chloride / Q000494:pharmacology*; D013011:Sorbic Acid / Q000494:pharmacology*
chemical_list: D000891:Anti-Infective Agents, Local; D004338:Drug Combinations; D012388:Root Canal Irrigants; D012965:Sodium Chloride; D002126:Calcium Hydroxide; D002710:Chlorhexidine; D013011:Sorbic Acid