Study on the Mechanism of Stain Removal by the Effect of Sodium Pyrophosphate

Abstract

Keeping the oral environment hygienic is effective in the prevention of oral diseases such as dental caries and periodontal disease, and is thought to be related to improving oral-related quality of life. Therefore, it is important to remove stains by daily tooth brushing as a way to maintain healthy oral environment. In this study, we focused on sodium pyrophosphate (PPNa) which is known to remove stains and is used in commercial toothpastes, to clarify the stain removal mechanism. The results showed that the thickness of the stain composed of proteins and polyphenols increased by applying PPNa to the stain on the tooth surface model. In addition, the particle size of the aggregates of the stain was reduced. These results suggested that the chelating effect of PPNa trapped Ca in the aggregates and decomposed them. It was also inferred that the increase in thickness of the stain made it easier to be removed by physical force. Furthermore, we examined the combined effect with a surfactant (sodium lauryl sulfate) and found that the stain removal effect was synergistically improved.