Antibacterial Efficacy Duration Comparisons of Commercial Stannous Fluoride Dentifrices

Objectives: This paper compares the longevity of antibacterial efficacy of Colgate Total^SF and Crest^® ProHealth^® Clean Mint (Procter & Gamble Co., Cincinnati, OH) by monitoring bacterial regrowth over time following a single treatment.
Methods: Collagen-coated, glass bottom 96-well plates were inoculated with Streptococcus gordonii DL-1 endogenously expressing green fluorescent protein (GFP) for approximately 4 hours. The adherent bacteria were treated with 1:2 (toothpaste:dH₂O) for two minutes at room temperature. The resulting treated S. gordonii were visualized by confocal laser scanning microscopy (CLSM) over a 12 hour time period and their z-stacks were analyzed using Python Software. For each time point, the stacks were decomposed into a sequence of images and each image was independently analyzed for the relative cell number. The total number of accumulated bacteria was the sum over the entire z-stack and biovolume expressed in voxels.
Results:

Time course studies documented in S. gordonii biofilm growth and accumulation following treatment with either Crest^® ProHealth^® Clean Mint or Colgate Total^SF. CLSM-obtained images showed significantly less biofilm accumulation (~30% reduction vs Crest^® ProHealth^®) over the 12 hour regrowth for the Colgate Total^SF. Mapping the re-growth kinetics between the two stannous-treated biofilms showed a relatively reduced growth induction starting at 4 hours post-treatment with the Colgate Total^SF-treated biofilm with significant inhibition of biofilm growth through the 12 hour experimental endpoint.
Conclusions:

These results indicate that the stannous fluoride dentifrice stabilized by zinc phosphate, Colgate Total^SF, provided improved protection against bacteria regrowth than Crest^® ProHealth^® Clean Mint. This advancement in dentifrice technology marks a significant improvement toward improving the overall oral health of consumers.