title: Diffusion of antimicrobials in multispecies biofilms evaluated in a new biofilm model.
abstract: OBJECTIVE
  To describe the application of a newly-developed in vitro model in which the diffusion of antimicrobials in oral biofilms can be studied.
  
  
  METHODS
  In a flow chamber consisting of three parallel feeding channels connected with each other by eight perpendicular side channels, multispecies biofilms were grown from saliva of a single donor for 48 h. The dimensions of the side channels were 100 μm × 100 μm × 5130 μm (H × W × L). When one or more side channels were filled with biofilm, the biofilms were stained with fluorescent stains. Then, one side-channel biofilm was selected and treated with phosphate buffered saline, 2% sodium hypochlorite (NaOCl), 17% ethylenediaminetetra-acetic acid (EDTA) or modified salt solution (MSS). Diffusion of the irrigants was observed by acquiring fluorescence images at 10× objective every 15 s for 30 min.
  
  
  RESULTS
  It was possible to culture biofilms in the narrow (100 μm) channels. The biofilms varied in phenotype. In this model, no diffusion of NaOCl into the biofilms was seen after its application. Seventeen-percentage EDTA only diffused into the biofilm up to 200 μm in 30 min. MSS did diffuse in the biofilm over a distance of 450 μm within 2 min after a single application.
  
  
  CONCLUSIONS
  This new model enables the investigation of the diffusion of antimicrobials in biofilms. Other applications to improve our understanding of the characteristics of biofilms are now possible.
authors.affiliation: Department of Cariology, Endodontology, Pedodontology, Academic Centre for Dentistry Amsterdam (ACTA), Amsterdam, The Netherlands.|Department of Preventive Dentistry, Academic Centre for Dentistry Amsterdam (ACTA), Amsterdam, The Netherlands.
authors.forename: S V
authors.initials: SV
authors.lastname: van der Waal
authors.affiliation: Department of Endodontics, School of Dentistry, Federal University of Santa Catarina, Florianópolis, SC, Brazil.
authors.forename: J
authors.identifier: http://orcid.org/0000-0002-6120-5996
authors.initials: J
authors.lastname: de Almeida
authors.affiliation: Department of Preventive Dentistry, Academic Centre for Dentistry Amsterdam (ACTA), Amsterdam, The Netherlands.
authors.forename: B P
authors.initials: BP
authors.lastname: Krom
authors.affiliation: Department of Preventive Dentistry, Academic Centre for Dentistry Amsterdam (ACTA), Amsterdam, The Netherlands.
authors.forename: J J
authors.initials: JJ
authors.lastname: de Soet
authors.affiliation: Department of Preventive Dentistry, Academic Centre for Dentistry Amsterdam (ACTA), Amsterdam, The Netherlands.
authors.forename: W
authors.initials: W
authors.lastname: Crielaard
mesh_terms: D000890:Anti-Infective Agents / Q000378:metabolism*; D018441:Biofilms / Q000187:drug effects; D004396:Coloring Agents / Q000378:metabolism; D004492:Edetic Acid / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D008954:Models, Biological; D012463:Saliva / Q000378:metabolism; D012965:Sodium Chloride / Q000378:metabolism; D012973:Sodium Hypochlorite / Q000378:metabolism
chemical_list: D000890:Anti-Infective Agents; D004396:Coloring Agents; D012965:Sodium Chloride; D004492:Edetic Acid; D012973:Sodium Hypochlorite
keywords: biofilm; diffusion; endodontic; ethylenediaminetetra-acetic acid; modified salt solution; sodium hypochlorite