Methods: Soluble free F ion in the neat toothpaste was measured by low resolution NMR and in toothpaste supernatant by ion selective electrode (ISE). NMR analysis was performed based on the method described by Oxford Instruments (“Determination of Fluoride Content in Toothpaste”, http://www.oxford-instruments.com/applicationsmarkets/health/Documents). Using NMR, fluoride calibration standards and neat test samples were scanned for F analysis. The concentration of F in ppm for the test samples was determined from the calibration curve based on the signal to mass ratio. Using ISE, toothpaste supernatants and calibration standards were prepared in accordance with FDA Monograph Method # 29. Test solutions and standards were measured, and the millivolt values were recorded. The concentration of F in ppm was determined based on the calibration curve.
Results: Results showed that PreviDent 5000 Booster had greater than 90% of the target soluble F ion recovery by both NMR and ISE. In contrast, NMR for Sensodyne®Nupro® 5000 sample revealed results below the detection limit. ISE results for Sensodyne®Nupro® 5000 indicated that less than 60% of the theoretical amount of soluble F ion was recovered in the supernatant. The diminished soluble F results for Sensodyne®Nupro® 5000 may be due to the presence of NovaMin®. Calcium from NovaMin® can interact with F ions to form CaF2, impacting soluble free fluoride levels in the formula. The amount of soluble fluoride delivered from a NaF dentifrice in-vitro is generally correlated with fluoride availability in-vivo.
Conclusions: These results indicate that PreviDent 5000 Booster has superior F availability as compared to Sensodyne®Nupro® 5000. Fluoride availability from Sensodyne®Nupro® 5000 is likely compromised due to the NovaMin® in the formulation.
Keywords: Calcium, Caries, Dentifrices, Fluoride and Solubility
See more of: Cariology Research - Fluoride and Ca-based Products