Quantification of endotoxins and cultivable bacteria in root canal infection before and after chemomechanical preparation with 2.5% sodium hypochlorite

J Endod. 2008 Mar;34(3):268-72. doi: 10.1016/j.joen.2007.11.015. Epub 2008 Jan 31.


This clinical study was conducted to quantify endotoxins and cultivable bacteria in teeth with pulp necrosis and apical periodontitis before and after chemomechanical preparation with 2.5% sodium hypochlorite (NaOCl) and to investigate the possible correlation of endotoxin and cultivable bacteria with the presence of clinical symptomatology. Twenty-four root canals were selected. Samples were collected before (s1) and after chemomechanical preparation (s2). Culture techniques were used to determine the colony-forming unit. A limulus amebocyte lysate (LAL) assay was used to quantify endotoxins (lipopolysaccharide, LPS). LPS and bacteria were detected in 100% of the initial samples (s1), with a median concentration of 139 endotoxin units/mL and 2.64 x 10(5) colony-forming units/mL, respectively. Higher levels of LPS were found in teeth with clinical symptomatology (p < .05). At s2, mean endotoxin reduction of 59.99% and mean bacterial load reduction of 99.78% were found. Our findings indicated that chemomechanical preparation with 2.5% NaOCl was moderately effective against bacteria but less effective against endotoxins in root canal infection. Furthermore, a statistically significant association was found between higher levels and clinical symptomatology.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Bacteria / isolation & purification
  • Colony Count, Microbial
  • Dental Pulp Necrosis / microbiology*
  • Endotoxins / analysis
  • Humans
  • Limulus Test
  • Middle Aged
  • Periapical Periodontitis / microbiology*
  • Root Canal Irrigants / therapeutic use*
  • Root Canal Preparation*
  • Sodium Hypochlorite / therapeutic use*


  • Endotoxins
  • Root Canal Irrigants
  • Sodium Hypochlorite