Effects of Amine-/Stannous Fluoride and Sodium Fluoride on CDFF Biofilm

Objective: To determine effects of amine-/stannous fluoride (AmF/SnF₂) and sodium fluoride (NaF) pulsing on the cariogenicity and acidogenicity of a nine species CDFF biofilm. Methods: A modified CDFF (mCDFF) (turntable can pivot) was inoculated with Streptococcus mutans, S. oralis, S. gordonii, Fusobacterium nucleatum, Actinomyces naeslundii, Veillonella parvula, Lactobacillus casei, Prevotella nigrescens and Neisseria perflava. Basic medium with hog gastric mucin and 1.5 mM CaCl₂ was used for 10 days to grow biofilms on enamel discs recessed to a depth of 600 µm. Then the mCDFF was placed into pivot mode to create a split design of the CDFF turntable. For 10 consecutive days, one side was pulsed twice daily with 250 ppm fluoride either as AmF/SnF₂)or as NaF and both sides were pulsed four times a day for 30 minutes with 28 mM glucose. Before and after the pulsing regime; biofilm composition, pH response and enamel lesions were assessed. Results: The glucose/fluoride pulsing promoted the growth of all bacteria and favoured of the caries associated bacteria S. mutans and V. parvula, irrespective of the type of fluoride used. pH response curves showed higher resting pH and increased acidogenicity in glucose/fluoride treated biofilms compared to the pre-pulse biofilms. Transversal micro radiography data showed no further de- nor remineralization in the specimens underneath the fluoride treated biofilms. Conclusion: The effects of AmF/SnF₂)treatment and NaF treatment in a nine species consortium grown in CDFF biofilm were similar regarding the biofilm composition, biofilm pH response and lesion formations underneath the biofilms.