title: In vitro evaluation of the action of irrigating solutions associated with intracanal medications on Escherichia coli and its endotoxin in root canals.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the efficacy of auxiliary chemical substances and intracanal medications on Escherichia coli and its endotoxin in root canals.
  
  
  METHODS
  Teeth were contaminated with a suspension of E. coli for 14 days and divided into 3 groups according to the auxiliary chemical substance used: G1) 2.5% sodium hypochlorite (NaOCl); G2) 2% chlorhexidine gel (CLX); G3) pyrogen-free solution. After, these groups were subdivided according to the intracanal medication (ICM): A) Calcium hydroxide paste (Calen®), B) polymyxin B, and C) Calcium hydroxide paste+2% CLX gel. For the control group (G4), pyrogen-free saline solution was used without application of intracanal medication. Samples of the root canal content were collected immediately after biomechanical preparation (BMP), at 7 days after BMP, after 14 days of intracanal medication activity, and 7 days after removal of intracanal medication. The following aspects were evaluated for all collections: a) antimicrobial activity; b) quantification of endotoxin by the Limulus Amebocyte Lysate test (LAL). Results were analyzed by the Kruskal-Wallis and Dunn's tests at 5% significance level.
  
  
  RESULTS
  The 2.5% NaOCl and CLX were able to eliminate E. coli from root canal lumen and reduced the amount of endotoxin compared to saline.
  
  
  CONCLUSIONS
  It was concluded that 2.5% NaOCl and CLX were effective in eliminating E. coli. Only the studied intracanal medications were to reduce the amount of endotoxin present in the root canals, regardless of the irrigant used.
authors.affiliation: Department of Restorative Dentistry, São Paulo State University, São José dos Campos, SP, Brazil. lilian.maekawa@uol.com.br
authors.forename: Lilian Eiko
authors.initials: LE
authors.lastname: Maekawa
authors.forename: Marcia Carneiro
authors.initials: MC
authors.lastname: Valera
authors.forename: Luciane Dias de
authors.initials: LD
authors.lastname: Oliveira
authors.forename: Cláudio Antonio Talge
authors.initials: CA
authors.lastname: Carvalho
authors.forename: Cristiane Yumi
authors.initials: CY
authors.lastname: Koga-Ito
authors.forename: Antonio Olavo Cardoso
authors.initials: AO
authors.lastname: Jorge
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002126:Calcium Hydroxide / Q000494:pharmacology; D002710:Chlorhexidine / Q000494:pharmacology; D003786:Dental Pulp Cavity / Q000737:chemistry / Q000382:microbiology*; D004731:Endotoxins / Q000032:analysis*; D004926:Escherichia coli / Q000187:drug effects*; D006801:Humans; D066298:In Vitro Techniques; D011112:Polymyxin B / Q000494:pharmacology; D012388:Root Canal Irrigants / Q000494:pharmacology*; D018915:Root Canal Preparation; D012973:Sodium Hypochlorite / Q000494:pharmacology; D018709:Statistics, Nonparametric
chemical_list: D000900:Anti-Bacterial Agents; D004731:Endotoxins; D012388:Root Canal Irrigants; C044101:endotoxin, Escherichia coli; D012973:Sodium Hypochlorite; D011112:Polymyxin B; D002126:Calcium Hydroxide; D002710:Chlorhexidine