Thursday, March 22, 2012: 3:30 p.m. - 4:45 p.m.
Presentation Type: Poster Session
Objectives: To develop an in-vitro biofilm method to grow mixed species biofilms in a modified drip flow reactor (MDFR) and to validate this method by testing the performance of Colgate Total® (CT) and Colgate Cavity Protection® (CCP). Background: The MDFR is derived from ASTM method E2647. It delivers a flow of medium over biofilms that are continuously cultured on saliva-conditioned hydroxyapatite coated slides, which allows researchers to grow biofilms representative of oral plaque on tooth like surfaces. Methods: A mixed species inoculum containing equal levels of Actinomyces viscosus (ATCC#43146), Fusobacterium nucleatum (ATCC#10953), Lactobacillus casei (ATCC#334), Veilonella parvula (ATCC#17745) and Streptococcus oralis (ATCC#35037) from a continuous culture chemostat was used to establish the biofilm for 2 hours in the static phase followed by incubation in a continuous flow phase with Modified Marsh Medium at a flow rate of 10mls/hour/chamber for 24 hours at 25ºC under aerobic conditions. Supernatants of dentifrice slurries (1:2 w/v) in water were then added to the biofilm for 2 minutes treatment followed by a second treatment at a 6-hr interval followed by a 24 hour continuous flow phase. Biofilms were harvested and quantified using both total anaerobic plate counts and quantitative real-time PCR analysis (qPCR) for total DNA. Results: The results showed a 1.29 log difference between CT and CCP as measured by plate counts analysis while the qPCR analysis provided a 1.54 log difference between the toothpastes. Conclusion: Both toothpastes CT and CCP were effective at reducing total anaerobes. CT showed statistically higher performance using both analytical methods (p<0.05). qPCR results showed greater separation since it measures total bacterial DNA of viable and non-viable bacteria. Additionally, qPCR allows for determination of effects on individual species providing a robust method for discriminating between the performances of a dentifrice containing a broad-spectrum antimicrobial versus a regular fluoride dentifrice.
Keywords: Biofilm, Dentifrices, Drip Flow, Microbiology and Nucleic acids
Presenting author's disclosure statement: David Santos is an employee for Colgate-Palmolive