title: Efficacy of natural antimicrobials in toothpaste formulations against oral biofilms in vitro.
abstract: OBJECTIVE
  To evaluate the antimicrobial efficacies of two toothpaste formulations containing natural antimicrobials (herbal extracts and chitosan) against oral biofilms of different composition and maturational status.
  
  
  METHODS
  Bacteria from a buffer suspension or fresh saliva were adhered for 2h to a salivary conditioning film and subsequently grown for 16h. Dual-species biofilms were prepared from Actinomyces naeslundii T14V-J1 and Streptococcus oralis J22, whilst multi-species biofilms were grown from freshly collected human saliva. Biofilms were exposed to 25wt% toothpaste supernatants. A chlorhexidine-containing mouthrinse and a buffer were used as positive- and negative-controls, respectively. Antibacterial efficacy was concluded from acute killing, bacterial removal, prevention of bacterial re-deposition and continued killing during re-deposition.
  
  
  RESULTS
  The herbal- and chitosan-based supernatants showed immediate killing of oral biofilm bacteria, comparable with chlorhexidine. Moreover, exposure of a biofilm to these supernatants or chlorhexidine, yielded ongoing killing of biofilm bacteria after exposure during re-deposition of bacteria to a matured 16h biofilm, but not to a much thinner initial biofilm formed by 2h adhesion only. This suggests that thicker, more matured biofilms can absorb and release oral antimicrobials.
  
  
  CONCLUSIONS
  Supernatants based on herbal- and chitosan-based toothpastes have comparable immediate and ongoing antibacterial efficacies as chlorhexidine. Natural antimicrobials and chlorhexidine absorb in oral biofilms which contributes to their substantive action.
authors.affiliation: Department of Biomedical Engineering, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: Martinus J
authors.initials: MJ
authors.lastname: Verkaik
authors.forename: Henk J
authors.initials: HJ
authors.lastname: Busscher
authors.forename: Debbie
authors.initials: D
authors.lastname: Jager
authors.forename: Anje M
authors.initials: AM
authors.lastname: Slomp
authors.forename: Frank
authors.initials: F
authors.lastname: Abbas
authors.forename: Henny C
authors.initials: HC
authors.lastname: van der Mei
mesh_terms: D000190:Actinomyces / Q000187:drug effects; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D000891:Anti-Infective Agents, Local / Q000494:pharmacology; D001422:Bacterial Adhesion / Q000187:drug effects; D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development; D048271:Chitosan / Q000494:pharmacology*; D002710:Chlorhexidine / Q000494:pharmacology; D018920:Coculture Techniques; D005260:Female; D006801:Humans; D008297:Male; D008422:Materials Testing; D050296:Microbial Viability / Q000187:drug effects; D009067:Mouthwashes / Q000494:pharmacology; D008517:Phytotherapy; D010936:Plant Extracts / Q000494:pharmacology*; D012463:Saliva / Q000382:microbiology*; D017693:Sodium Bicarbonate / Q000494:pharmacology; D019533:Streptococcus oralis / Q000187:drug effects; D013997:Time Factors; D014100:Toothpastes / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D000891:Anti-Infective Agents, Local; D009067:Mouthwashes; C091016:Parodontax; D010936:Plant Extracts; D014100:Toothpastes; D017693:Sodium Bicarbonate; D048271:Chitosan; D002710:Chlorhexidine