title: Detoxification of endotoxin by endodontic irrigants and calcium hydroxide.
abstract: The effects of endodontic irrigants and calcium hydroxide on lipopolysaccharide (LPS; endotoxin) were analyzed using the highly selective technique of mass spectrometry/gas chromatography with selected ion monitoring. An aqueous solution of LPS was mixed with one of a variety of endodontic irrigants for 30 min. Because it is a commonly used interappointment dressing, calcium hydroxide was also applied to LPS for 1, 2, or 5 days. LPS inactivation was measured by quantitation of free fatty acid release. Water, EDTA, ethanol, 0.12% chlorhexidine, chlorhexidine + sodium hypochlorite, and sodium hypochlorite alone showed little breakdown of LPS. Long-term calcium hydroxide--as well as 30-min exposure to an alkaline mixture of chlorhexidine, ethanol, and sodium hypochlorite--did detoxify LPS molecules by hydrolysis of ester bonds in the fatty acid chains of the lipid A moiety.
authors.affiliation: University of Louisville, KY, USA.
authors.forename: R A
authors.initials: RA
authors.lastname: Buck
authors.forename: J
authors.initials: J
authors.lastname: Cai
authors.forename: P D
authors.initials: PD
authors.lastname: Eleazer
authors.forename: R H
authors.initials: RH
authors.lastname: Staat
authors.forename: H E
authors.initials: HE
authors.lastname: Hurst
mesh_terms: D001431:Bacteriological Techniques; D002126:Calcium Hydroxide / Q000494:pharmacology*; D002849:Chromatography, Gas; D004731:Endotoxins / Q000037:antagonists & inhibitors* / Q000737:chemistry; D017736:Ion-Selective Electrodes; D008050:Lipid A / Q000032:analysis / Q000737:chemistry; D008066:Lipolysis; D008070:Lipopolysaccharides / Q000737:chemistry*; D013058:Mass Spectrometry; D009227:Myristic Acids / Q000032:analysis / Q000737:chemistry; D011135:Polysaccharides, Bacterial / Q000187:drug effects*; D012388:Root Canal Irrigants / Q000494:pharmacology*
chemical_list: D004731:Endotoxins; D008050:Lipid A; D008070:Lipopolysaccharides; D009227:Myristic Acids; D011135:Polysaccharides, Bacterial; D012388:Root Canal Irrigants; C009893:beta-hydroxymyristic acid; D002126:Calcium Hydroxide