Ions Release From 3M Vanish^TM Varnish At Different pH Conditions

Objectives: Ion release is an important property for dental varnish. 3M Vanish^TM 5% sodium fluoride Varnish contains fluoride, calcium and phosphate. This study investigated ion release of Vanish^TM under several pH conditions.
Methods: Solutions of different pH were prepared by bubbling acetic acid or ammonia gas into neutral deionized water to avoid other ion contamination. Approximately 50mg of Vanish^TM (lot N652461) was painted onto plastic slides (N=5) for each condition. These slides were immersed in 25ml of acidic, neutral and basic water solutions separately for 1 hour at 37^oC. After 1 hour, solutions were collected. Slides were rinsed and immersed in 25ml new solution for continued release. Solutions were collected at 4, 6, 24 hours. The samples were analyzed for fluoride ion concentration with a fluoride ion electrode, and calcium and phosphate ion concentrations were measured by ICP-AES. Data were analyzed using one-way ANOVA Tukey Pairwise Comparison.
Results: Fluoride, calcium and phosphate ion concentrations at different conditions are summarized in the following table. Groups in each column with different letters were statistically different.
Conclusions: 3M Vanish^TM fluoride Varnish releases fluoride, calcium and phosphate ions at different rates depending on pH. ANOVA analysis performed at p <0.05 showed significantly different cumulative amounts of fluoride, calcium and phosphate ions released at different pHs. Ion release increases for all three ions as pH decreases. 3M Vanish^TM 5% sodium fluoride Varnish releases more ions when the solution becomes acidic and teeth are most at risk.