Hydrogen Peroxide Toothpaste Reduces a Broad Range of Tooth Stains

Objectives: Tooth stains can arise from the use of various food and consumer products which contain chromophores that deposit on teeth. Therefore, methods to effectively test the whitening efficacy of toothpastes in vitro must encompass a broad range of stains. In this study a method to substantively stain bovine teeth with chromogens from coffee, red wine, and soda was developed. A toothpaste containing 2% H₂O₂ was evaluated for its ability to reduce in vitro generated stain compared to a negative control toothpaste without H₂O₂.
Methods: Sourced bovine teeth mounted on an acrylic resin were etched. Staining of bovine teeth was performed for two weeks using a bacterial broth containing a combination of coffee, red wine, and soda. Teeth were brushed until initial L* values approached those of naturally stained human teeth (60 to 68). Twelve teeth were mounted (4 per tray) and baseline L*, a*, and b* values were measured with a Spectroshade spectrophotometer. Teeth were brushed for two minutes with a 1:1 (w/w) toothpaste – artificial saliva slurry and rinsed with water. This process was repeated a total of 14 times to model one week of twice daily brushing. After 14 brushing cycles, the L*, a*, and b* values were measured again. The Whiteness index, ΔW* (where W*= ((L*-100)² + a*² + b*²)^1/2) was reported after 14 brushing treatments. Analysis of variance using baseline as a covariate was performed to compare the mean ΔW* values for each product with p<0.05 indicating statistically significant differences between products.
Results: A method to substantively impart a broad range of stains derived from coffee, red wine, and soda on bovine teeth was developed. The in vitro whitening activity of the toothpaste containing 2% H₂O₂ is statistically significantly (p<0.05) better than the whitening activity of a toothpaste without H2O2.
Conclusions: The model developed can differentiate toothpaste’s ability to reduce stains. The toothpaste containing 2% H₂O₂ effectively reduced stains caused by coffee, red wine and soda when compared to toothpaste without H2O2.