Objectives: 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 2 h to a salivary conditioning film and subsequently grown for 16 h. 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 25 wt% 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 16 h biofilm, but not to a much thinner initial biofilm formed by 2 h 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. © 2010 Elsevier Ltd. All rights reserved.
Verkaik, M. J., Busscher, H. J., Jager, D., Slomp, A. M., Abbas, F., & Van Der Mei, H. C. (2011). Efficacy of natural antimicrobials in toothpaste formulations against oral biofilms in vitro. Journal of Dentistry, 39(3), 218–224. https://doi.org/10.1016/j.jdent.2010.12.007