Characterization and effect of nanocomplexed fluoride solutions on the inhibition of enamel demineralization created by a multispecies cariogenic biofilm model.

Abstract

The aim of this study was to assess the in vitro caries preventive effect of nanocomplexed solutions of hydroxypropyl-β-cyclodextrin and γ-cyclodextrin associated with titanium tetrafluoride (TiF4) after different complexation times (12 or 72h). Enamel blocks were randomly distributed in 9 groups (n = 11): negative control, hydroxypropyl-β-cyclodextrin, γ-cyclodextrin, TiF4, hydroxypropyl-β-cyclodextrin:TiF4 12h, hydroxypropyl-β-cyclodextrin:TiF4 72h, γ-cyclodextrin:TiF4 12h, γ-cyclodextrin:TiF4 72h, and NaF (positive control). The solutions were applied for 1min and the blocks were exposed to a biofilm model. Nanocompounds were characterized by differential scanning calorimetry and X-ray powder diffraction. The percentage of surface microhardness loss (%SML), mineral density changes (ΔZ), lesion depth, surface morphology (scanning electron microscopy-SEM), and chemical characterization (energy-dispersive spectroscopy-EDS) were assessed. No oxidation was observed, and the formation of the nanocomplexes was evidenced by changes in the melting point compared to pure cyclodextrins and the loss of crystallinity of the materials. Hydroxypropyl-β-cyclodextrin:TiF4 72h resulted in lower %SML than negative control, hydroxypropyl-β-cyclodextrin, γ-cyclodextrin, and TiF4 (p< 0.05). NaF differed from all groups (p< 0.05), except for hydroxypropyl-β-cyclodextrin:TiF4 72h (p= 0.83). ΔZ of hydroxypropyl-β-cyclodextrin:TiF4 72h was higher than negative control, hydroxypropyl-β-cyclodextrin, γ-cyclodextrin, γ-cyclodextrin:TiF4 1 2h, γ-cyclodextrin:TiF4 72h, and NaF (p< 0.05) and similar to TiF4 and hydroxypropyl-β-cyclodextrin:TiF4 12h (p> 0.05). SEM/EDS detected Ti in the blocks subjected to TiF4-products. The hydroxypropyl-β-cyclodextrin:TiF4 72h solution showed caries preventive effect on the surface and subsurface of the enamel. A hydroxypropyl-β-cyclodextrin nanosystem, in association with TiF4 after 72h of complexation, may be a promising agent for the prevention of enamel demineralization.