Strengthening Enamel to Help Prevent Tooth Surface Loss

Tooth health can be measured not only by prevention against subsurface damage (caries) but also by assessing the ability of products to strengthen and protect enamel against the initial enamel softening that can lead to irreversible damage. Objectives: Purpose of this study was to determine the relative ability of various fluoride (F) salts to protect enamel against the initiation and progression of damage due to dietary acids. Methods: Cores of extracted, human enamel were cleaned, ground and polished, providing a virgin enamel surface, soaked in pooled saliva (pellicle formation), and treated with a 1:3 slurry (product:saliva) of toothpaste representing three F salts commonly used in toothpastes (a:NaF; b:NaMFP; c:SnF2). Specimens were subjected to pH cycling conditions (5 day model) that included: Study 1) 1% citric acid challenges; and Study 2) marketed cola (phosphoric acid) challenges. Together, these studies represent challenges to the enamel by common food based acids. Results: SnF2 treated specimens resulted in 10.3 and 2.0 microns of enamel lost (citric and phosphoric acid, respectively). NaF and NaMFP treated specimens resulted in 24.5/12.8um (citric/phosphoric) and 28.0/14.9um (citric/ phosphoric) of total mineral loss, respectively. These studies suggest citric acid is more aggressive than phosphoric acid, and both studies demonstrate clearly superior protection against acid challenge attributed to the SnF2 formulation tested, with SnF2 providing a 58.2% reduction in acid mediated damage (vs. the NaF control) for citric acid, and a reduction of 84% (vs. NaF) when tested using a phosphoric acid challenge. Conclusions: These results clearly demonstrate SnF2 provides superior protection to the tooth enamel against common dietary acid attacks. Due to the potentially irreversible nature of erosive acid damage, development of products designed to help prevent damage initiation and progression is key to providing meaningful tooth health benefits.