There is a misconception that “all fluorides are the same”. That’s simply not true. Stannous fluoride is unique among fluoride compounds, offering multiple benefits not found with sodium fluoride or sodium monofluorophosphate. While all three compounds provide anti-caries benefits, stabilized stannous fluoride has demonstrated broader and significantly greater protection than other fluorides against plaque (Sharma et al. 2013; Garcia-Godoy et al. 2015), gingivitis (Archila et al. 2004; Mallatt et al. 2007), erosion (Hooper et al. 2007; West et al. 2017), sensitivity (Schiff et al. 2005; He et al. 2011) and halitosis (Farrell et al. 2007). (See Table 1)
Table 1. Stannous fluoride offers broader and greater protection relative to other fluorides.
So why isn’t stannous fluoride used in every dentifrice? Stannous fluoride has some inherent challenges to formulate, requiring skill and expertise to ensure it is delivered in a bioavailable, esthetically pleasing dentifrice (White 2013). These challenges can be overcome by including extrinsic whitening agents and ingredients to stabilize the stannous fluoride (e.g., chelants), but it’s not a simple process. The following section describes decades of innovations by Procter & Gamble resulting in the largest portfolio of stabilized stannous fluoride dentifrices available to improve patients’ oral health and provide a brushing experience that delights them. (See Figure 1)
The anti-caries benefit of fluoride was confirmed in the mid-1940s (Dean et al. 1942). However, an effective anti-caries dentifrice was not brought to market until 1955, when Procter & Gamble and collaborators at Indiana University became the first to successfully formulate stannous fluoride into a clinically proven dentifrice, with caries reductions of up to 53% (Muhler et al. 1954). The stannous fluoride in this early dentifrice had limited stability. While the product delivered an anti-caries benefit, the full therapeutic benefits of stannous fluoride were not realized. Subsequently, the stannous fluoride in daily use dentifrice was replaced with more stable fluoride products, mainly sodium monofluorophosphate and sodium fluoride. However, P&G maintained interest in stannous fluoride because of the unique potential of this compound to also provide gingival health and anti-hypersensitivity benefits.
By the early 1990s, stannous fluoride systems had been stabilized and reformulated with a new abrasive system in the formulation. During this era, there was also more focus from the dental professional community on plaque and gingivitis control. After researching a number of formulations, a new stabilized stannous dentifrice (Crest® Gum Care) was launched in the mid-1990s focused on periodontal health (White 1995). The reception was mixed. The new dentifrice was highly effective at plaque and gingivitis control as well as caries prevention. Trade-offs persisted, however, such as a lack of anti-tartar effect and some extrinsic staining. The challenge was how to provide therapeutic benefits, while concurrently providing cosmetic benefits of tooth whitening and tartar control.
Figure 1. A timeline of stannous fluoride dentifrice innovations
A series of inventions by P&G ultimately led to the formulation of a stabilized stannous fluoride dentifrice with an advanced anti-calculus and whitening agent, sodium hexametaphosphate (Baig & He 2005). This was the first truly multi-benefit dentifrice offering the full array of therapeutic benefits afforded by stannous fluoride, in addition to the tooth whitening and anticalculus benefits that are important to consumers. The formulation was marketed across the globe as Crest® PRO-HEALTH™ or Oral-B® Pro-Expert, depending on the region. The first key invention leading to this breakthrough included developing chemical approaches to protect the stannous ion from inactivation by oxidation and hydrolysis which typically occur when stannous fluoride is formulated into a dentifrice. Second, groundbreaking research on tartar control agents led to the discovery of sodium hexametaphosphate, a powerful whitening and anti-calculus ingredient. Third, developing methods to formulate a low-water dentifrice (<3% water vs. 20-70% water in typical dentifrices) allowed stannous fluoride and sodium hexametaphosphate to be combined into one dentifrice formulation that provides stability to both ingredients and allows them to co-exist in the same formulation to deliver their unique benefits.
The current decade has seen three more innovations in the Procter & Gamble stabilized stannous fluoride dentifrice portfolio to further enhance efficacy and provide esthetic alternatives to meet different patient preferences:
Each stabilized stannous fluoride dentifrice provides multiple mechanisms of action and delivers multiple benefits. In addition to the anti-caries benefit of stannous fluoride, the actions of stannous fluoride against oral bacteria impart effectiveness against plaque, gingivitis, and halitosis (Baig & He 2005). Stannous fluoride also promotes the occlusion of open dentinal tubules associated with hypersensitivity and binds to the enamel surfaces to protect against acid erosion (Zsiska et al. 2011, Faller & Eversole 2014). Additionally, tooth whitening and calculus control are delivered by sodium hexametaphosphate or other ingredients, depending on the specific formulation (Schiff et al. 2005, Terezhalmy et al. 2007, Farrell et al. 2016, Friesen et al. 2017).
The following pages address the mechanisms of action and efficacy of the stabilized stannous fluoride dentifrice formulas for each important oral care benefit.