title: A scanning electron microscope study on the effect of an experimental irrigation solution on smear layer removal.
abstract: BACKGROUND
  The aim of this in vitro study was to evaluate the effect of an experimental irrigation solution, containing two different concentrations of papain, Tween 80, 2% chlorhexidine and EDTA, on removal of the smear layer.
  
  
  METHODS
  Thirty-six single-rooted teeth were divided into two experimental groups (n=12) and two positive and negative control groups of six. The canals were prepared with BioRaCe instruments up to BR7 (60/0.02). In group 1, canals were irrigated with a combination of 1% papain, 17% EDTA, Tween 80 and 2% CHX; in group 2, canals were irrigated with a combination of 0.1% papain, 17% EDTA, Tween 80 and 2% CHX. In group 3 (the negative control), the canal was irrigated with 2.5% NaOCl during instrumentation and at the end of preparation with 1 mL of 17% EDTA was used; in group 4 (positive control), normal saline was used for irrigation. The amount of the remaining smear layer was quantified according to Hulsmann method using scanning electron microscopy (SEM). Data was analyzed by the Kruskal-Wallis and Mann-Whitney tests.
  
  
  RESULTS
  Two-by-two comparisons of the groups revealed no significant differences in terms of smear layer removal at different canal sections between the negative control group (standard regiment for smear layer removal) and 1% papain groups (P<0.05).
  
  
  CONCLUSIONS
  Under the limitations of the present study, combination of 1% papain, EDTA, 2% chlorhexidine and Tween 80 can effectively remove smear layer from canal walls.
authors.affiliation: Dental and Periodontal Research Center, Department of Endodontics, Dental School, Tabriz University of Medical Sciences, Tabriz, Iran;
authors.forename: Vahid
authors.initials: V
authors.lastname: Zand
authors.affiliation: Dental and Periodontal Research Center, Department of Endodontics, Dental School, Tabriz University of Medical Sciences, Tabriz, Iran;
authors.forename: Hadi
authors.initials: H
authors.lastname: Mokhtari
authors.affiliation: Department of Endodontics, Dental School, Tabriz University of Medical Sciences, Tabriz, Iran;
authors.forename: Mehrdad
authors.initials: M
authors.lastname: Lotfi
authors.affiliation: Dental and Periodontal Research Center, Department of Endodontics, Dental School, Tabriz University of Medical Sciences, Tabriz, Iran;
authors.forename: Saeed
authors.initials: S
authors.lastname: Rahimi
authors.affiliation: Dental and Periodontal Research Center, Department of Orthodontics, Dental School, Tabriz University of Medical Sciences, Tabriz, Iran;
authors.forename: Aydin
authors.initials: A
authors.lastname: Sohrabi
authors.affiliation: Department of Prosthodontics, Dental School, Hamedan University of Medical Sciences, Hamedan, Iran;
authors.forename: Sina
authors.initials: S
authors.lastname: Badamchi Zadeh
authors.affiliation: Department of Endodontics, Faculty of Dentistry, Hamedan University of Medical Sciences, Hamedan, Iran;
authors.forename: Hanieh
authors.initials: H
authors.lastname: Mojaver Kahnamooie
authors.affiliation: Dental and Periodontal Research Center, Department of Operative Dentistry, Faculty of Dentistry, Tabriz University of Medical Sciences, Tabriz, Iran.
authors.forename: Pardis
authors.initials: P
authors.lastname: Tehranchi
keywords: EDTA; NaOCl; Papain; SEM; Scanning Electron Microscopy; Smear Layer