Stannous Fluoride

Stannous fluoride has been shown to be effective in the prevention of dental caries,35 reduction of plaque formation,36 control of gingivitis37 and the suppression of breath malodor.38 Research also shows stannous fluoride is effective against dentinal hypersensitivity.39-48 The ADA has recognized the desensitizing properties of stannous fluoride by granting the ADA Seal of Acceptance to a non-aqueous stannous fluoride gel formulation (Gel-Kam) for the therapeutic prevention of sensitivity and caries as well as to Crest® PRO-HEALTH® toothpaste.21

In situ research shows root dentin treated with stannous fluoride exhibits tubule occlusion at the surface by the formation of a smear layer (Figure 6).39 When the tubules are blocked, fluid flow is limited and the stimulation of the mechanoreceptors does not occur, thus preventing the pain response.

Figure 6a. Open tubules following treatment with non-sensitivity fluoride toothpaste.
Image: Open tubules.
Figure 6b. Closed tubules following treatment with SnF2 dentifrice.
Image: Closed tubules.

Stannous fluoride has been delivered via a mouth rinse, dentifrice, and gel for some time. Research by Thrash et al.43,44 in the 1990’s suggested there is a gradual decrease in sensitivity starting at two weeks and continuing throughout the 16-week period from initiation of treatment. Thrash and colleagues conducted a two-phase experimental design study comparing a 0.4% stannous fluoride gel to an aqueous 0.717% fluoride solution and a placebo to evaluate the effect of the products on hypersensitivity tooth pain and to determine the precise time of onset of any effect on dentinal hypersensitivity. Sensitivity to thermal stimuli was assessed prior to the first application and then at 2, 4, 8, and 16 week intervals after the initial application. The results indicated subjects who applied the 0.4% stannous fluoride gel reported significantly less sensitivity during the four to eight week period. The stannous fluoride gel resulted in the lowest mean threshold temperature compared to the other products.

Historically, one limitation to the use of stabilized stannous fluoride has been the potential for temporary extrinsic tooth staining associated with the long-term use of these products. Due to advances in dentifrice technology, this occurrence has been mitigated by incorporating sodium hexametaphosphate, an advanced tartar control and whitening ingredient, in the formulation marketed as Crest® PRO-HEALTH® toothpaste.

In two randomized, double-blind clinical trials, this stabilized stannous fluoride toothpaste significantly reduced thermal and tactile sensitivity versus a negative control.49,50 More recently, He et al, demonstrated in two different randomized controlled clinical trials that twice daily brushing with the stabilized stannous fluoride dentifrice provides superior dentinal hypersensitivity improvement versus a marketed sodium fluoride dentifrice, and a dentifrice containing 8.0% arginine, calcium carbonate and sodium monofluorophosphate.51,52 The stannous fluoride dentifrice provided some relief after the first brushing relative to each control, with the benefit growing larger over the study period with twice daily use. When compared to sodium fluoride/triclosan dentifrice, there was a similar outcome, superior dentinal hypersensitivity improvement with significant greater relief after two weeks and a larger benefit at eight weeks with twice daily brushing.53 In separate clinical research, this unique dentifrice provided significant extrinsic whitening relative to a positive control.53,54

In addition to the product mentioned above, a 2-step system that includes stannous fluoride dentifrice as the first step and hydrogen peroxide whitening gel at the second step has been shown to provide significantly better sensitivity relief than potassium nitrate sodium fluoride dentifrice.55