Stannous fluoride exerts antibacterial effects by two modes of action. First, stannous fluoride exerts a killing effect on bacteria (bactericidal action). This is probably due to non-specific interaction with the bacterial membrane that causes membrane disruption. The result is leakage of cellular components that leads to cell lysis and death.
The second, and more important, mode of antibacterial activity is through stannous fluoride’s inhibition of metabolic enzymes. The inhibition of metabolic activity affects bacteria in a number of ways, including:46,47
Stannous fluoride’s inhibitory effect on bacteria is related to its inhibition of bacterial glycolysis, an energy making process whereby metabolic enzymes break down carbohydrates. In addition, studies have demonstrated that stannous fluoride significantly reduces metabolic toxins produced by bacteria in plaque biofilm.46,47
In early stannous fluoride dentifrice formulations, the stannous fluoride was not fully stable or bioavailable. A key issue in formulating with stannous fluoride is that it is easily inactivated by hydrolysis and oxidation, thus making it difficult to stabilize in a typical dentifrice formula. Stannous fluoride can also have an astringent taste and cause extrinsic staining of teeth and fillings. However, current stannous fluoride-containing dentifrices have been formulated that circumvent instability and bioavailability challenges.
One of the major breakthroughs in stannous fluoride formulation efforts was due to technology innovations that enabled the combination of both whitening and stabilization chemistries to provide highly effective stannous fluoride formulations that are not compromised by common esthetic negatives, such as poor taste or staining, of earlier stannous fluoride products.23,48,49 After more than fifty years of research, P&G successfully formulated the first stabilized, consumer-acceptable, stannous fluoride dentifrice with the launch of Crest® PRO-HEALTH® dentifrice in 2005.23,24,48,49 Crest® PRO-HEALTH® dentifrice (Figure 9) carries the ADA Seal of Acceptance in the therapeutic categories of caries, gingivitis and sensitivity.