title: Chelating and antibacterial properties of chitosan nanoparticles on dentin.
abstract: OBJECTIVE
  The use of chitosan nanoparticles (CNPs) in endodontics is of interest due to their antibiofilm properties. This study was to investigate the ability of bioactive CNPs to remove the smear layer and inhibit bacterial recolonization on dentin.
  
  
  METHODS
  One hundred bovine dentin sections were divided into five groups (n = 20 per group) according to the treatment. The irrigating solutions used were 2.5% sodium hypochlorite (NaOCl) for 20 min, 17% ethylenediaminetetraacetic acid (EDTA) for 3 min and 1.29 mg/mL CNPs for 3 min. The samples were irrigated with either distilled water (control), NaOCl, NaOCl-EDTA, NaOCl-EDTA-CNPs or NaOCl-CNPs. After the treatment, half of the samples (n = 50) were used to assess the chelating effect of the solutions using portable scanning electronic microscopy, while the other half (n = 50) were infected intra-orally to examine the post-treatment bacterial biofilm forming capacity. The biovolume and cellular viability of the biofilms were analysed under confocal laser scanning microscopy. The Kappa test was performed for examiner calibration, and the non-parametric Kruskal-Wallis and Dunn tests (p < 0.05) were used for comparisons among the groups.
  
  
  RESULTS
  The smear layer was significantly reduced in all of the groups except the control and NaOCl groups (p < 0.05). The CNPs-treated samples were able to resist biofilm formation significantly better than other treatment groups (p < 0.05).
  
  
  CONCLUSIONS
  CNPs could be used as a final irrigant during root canal treatment with the dual benefit of removing the smear layer and inhibiting bacterial recolonization on root dentin.
authors: Department of Dentistry, Endodontics and Dental Materials, Bauru Dental School, University of São Paulo, Bauru-São Paulo, Brazil.
authors: Aldo
authors: A
authors: Del Carpio-Perochena
authors: Department of Dentistry, Endodontics and Dental Materials, Bauru Dental School, University of São Paulo, Bauru-São Paulo, Brazil.
authors: Clovis Monteiro
authors: CM
authors: Bramante
authors: Department of Dentistry, Endodontics and Dental Materials, Bauru Dental School, University of São Paulo, Bauru-São Paulo, Brazil.
authors: Marco Antonio Hungaro
authors: MA
authors: Duarte
authors: Department of Physics and Chemistry, FEIS, São Paulo State University, Ilha Solteira-São Paulo, Brazil. ; National Nanotechnology Laboratory for Agriculture, Embrapa, São Carlos-São Paulo, Brazil.
authors: Marcia Regina
authors: MR
authors: de Moura
authors: Department of Physics and Chemistry, FEIS, São Paulo State University, Ilha Solteira-São Paulo, Brazil.
authors: Fauze Ahmad
authors: FA
authors: Aouada
authors: Discipline of Endodontics, Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada.
authors: Anil
authors: A
authors: Kishen
keywords: Biofilm; Chitosan; Dentin; Nanoparticles; Recolonization