title: Physical disruption of oral biofilms by sodium bicarbonate: an in vitro study.
abstract: OBJECTIVE
  Sodium bicarbonate has been shown clinically to be efficacious at removing dental plaque; however, its effect of mechanism against biofilms has not been evaluated in vitro. Here, we used a well-established in vitro plaque biofilm model to investigate the disruption of dental plaque biofilms.
  
  
  METHODS
  Biofilms were grown in a constant depth film fermentor for up to 14 days. The fermentor was inoculated with pooled human saliva and growth maintained with artificial saliva. After various time points, replicate biofilms were removed and subjected to treatment at varying concentrations of sodium bicarbonate. Disruption of the plaque was assessed by viable counts and microscopy.
  
  
  RESULTS
  The viable count results showed that younger biofilms were less susceptible to the action of sodium bicarbonate; however, biofilms of 7 days and older were increasingly susceptible to the material with the oldest biofilms being the most susceptible. Sixty-seven percentage of sodium bicarbonate slurry was able to reduce the number of organisms present by approx. 3 log10 . These quantitative data were corroborated qualitatively with both confocal and electron microscopy, which both showed substantial qualitative removal of mature biofilms.
  
  
  CONCLUSIONS
  The results from this study have shown that sodium bicarbonate is able to disrupt mature dental plaque grown in vitro and that its reported efficacy in maintaining oral hygiene may be related to this key factor.
authors.affiliation: GlaxoSmithKline Consumer Healthcare, Weybridge, Surrey, UK.
authors.forename: J
authors.initials: J
authors.lastname: Pratten
authors.affiliation: UCL Eastman Dental Institute, London, UK.
authors.forename: J
authors.initials: J
authors.lastname: Wiecek
authors.affiliation: UCL Eastman Dental Institute, London, UK.
authors.forename: N
authors.initials: N
authors.lastname: Mordan
authors.affiliation: GlaxoSmithKline Consumer Healthcare, Weybridge, Surrey, UK.
authors.forename: A
authors.initials: A
authors.lastname: Lomax
authors.affiliation: GlaxoSmithKline Consumer Healthcare, Weybridge, Surrey, UK.
authors.forename: N
authors.initials: N
authors.lastname: Patel
authors.affiliation: UCL Eastman Dental Institute, London, UK.
authors.forename: D
authors.initials: D
authors.lastname: Spratt
authors.affiliation: GlaxoSmithKline Consumer Healthcare, Weybridge, Surrey, UK.
authors.forename: A M
authors.initials: AM
authors.lastname: Middleton
mesh_terms: D001419:Bacteria / Q000187:drug effects / Q000254:growth & development; D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development*; D019149:Bioreactors; D015169:Colony Count, Microbial; D003773:Dental Plaque / Q000188:drug therapy* / Q000382:microbiology; D018613:Microscopy, Confocal; D008854:Microscopy, Electron; D009910:Oral Hygiene; D012463:Saliva; D012464:Saliva, Artificial; D017693:Sodium Bicarbonate / Q000008:administration & dosage / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D012464:Saliva, Artificial; D017693:Sodium Bicarbonate
keywords: confocal microscopy; dental biofilm; in vitro model; sodium bicarbonate