Abstract
Objective: To explore the anti-caries efficacy of three fluoride compounds at increasing maturation of a microcosm biofilm.
Design: Microcosm biofilm, obtained from saliva collected from three donors (IRB #1406440799), was grown on enamel samples (n=18/group) for 24-h (Brain Heart Infusion; 0.2 % sucrose). Then, pH cycling model started. Three maturations were explored (4d, 8d, and 12d). The pH cycling consisted of daily 2x5 min treatments (NaF, SnF2, AmF: 287.5 ppm F, and de-ionized water [DIW]), 4x10 min remineralization (BHI, no sucrose, pH 7.0), and 3x2:15 h demineralization (BHI, 1% sucrose, pH 4.5). We analyzed the enamel (surface microhardness [VHNchange], integrated mineral loss [Delta Z], lesion depth [L]), and the biofilm (viability [log(10) CFU/mL], lactic acid production [LDH], and exopolysaccharide [EPS] amount). Data were analyzed using two-way ANOVA (p=0.05).
Results: The interaction between tested variables was significant for VHNchange, viability, LDH, EPS (p=0.0354, p=0.0001, p<0.0001, p<0.0001), but not for L (p=0.2412) or Delta Z (p=0.6811). LDH and EPS analyses exhibited more tolerance of mature biofilm against NaF (LDH and EPS p<0.0001); NaF-treated groups demonstrated significantly lower results than the control in the 12d group. The effect of SnF2 and AmF continued over time. VHNchange, L, and Delta Z: The effect of SnF2 and AmF was higher than NaF and DIW. L and Delta Z did not result in significant differences over time (all treatments). Within each maturation, fluoride compounds demonstrated statistically significantly lower L and.Z values than DIW.
Conclusions: Biofilm's maturation may influence the selection of fluoride compounds to achieve an optimum cariostatic effect.