Dental erosion is characterized by the dissolution and removal of the tooth enamel surface under highly acidic conditions. When the localized pH drops below approximately 4.5, the pellicle cannot protect the enamel surface, and irreversible erosive damage can occur. Enamel erosion has become an important issue with the increased consumption of sports drinks, soft drinks, and citric juices.31 All of these products have a pH below the critical level for dissolving dental enamel. In this context, the enamel erosion benefits of existing dentifrice ingredients has become more relevant and are described below.32-24
Fluoride (in general)
The mechanism by which fluoride helps prevent caries is the same mechanism by which it provides some dental erosion benefit. Fluoride exerts an effect by favoring remineralization and inhibiting demineralization.2,9,16
The presence of bioavailable fluoride in the oral fluids (i.e., biofilm and saliva) greatly enhances the crystallization of fluorapatite into tooth structure from calcium and phosphate ions present in saliva. Fluorapatite is more resistant to demineralization than hydroxyapatite, and thus provides some minimal level of enamel erosion benefit; but even fluorapatite will dissolve under highly acidic conditions.
In addition to the modest level of enamel erosion protection provided by fluoride in general, stannous fluoride is unique in its ability to provide significantly greater levels of protection compared to other fluoride sources.35-41 This is because stannous fluoride adheres to the surface of tooth enamel and forms a protective layer that is able to shield enamel from the effects of erosive acids.42-45