Distribution of fluoride and calcium in plaque biofilms after the use of conventional and low-fluoride dentifrices

Background: The distribution of fluoride and calcium in plaque after the use of fluoride dentifrices has not yet been determined. Aim: To evaluate fluoride and calcium distribution in sections of biofilms generated in situ after the use of conventional and low-fluoride dentifrices. Design: Children (n = 11, 8-10 years old) brushed with placebo (fluoride-free), low-fluoride (513 mgF/kg), and conventional (1072 mgF/kg) dentifrices twice daily for 1 week, following a double-blind, cross-over protocol. Biofilms were generated using Leeds in situ devices, which were collected 1 and 12 h after brushing, and sectioned through their depth. Sections were grouped (10 × 5 μm) for fluoride and calcium analysis. Sections 4 μm thick were used for image analysis and determination of biomass fraction. Results were analysed by anova, Tukey's test, and linear regression analysis (P < 0.05). Results: Fluoride and calcium were mostly located at the outer sections of biofilms for all dentifrices tested, and these ions were directly correlated throughout most of biofilm's sections. Results for conventional dentifrice were significantly higher than for the placebo, but did not differ from those for the low-fluoride dentifrice. Conclusions: The use of a low-fluoride dentifrice did not promote a higher fluoride uptake in inner biofilms' sections, as hypothesized. As plaque fluoride was significantly elevated only after the use of the conventional dentifrice, the recommendation of low-fluoride formulations should be done with caution, considering both risks and benefits

In vitro evaluation of fluoride products in the development of carious lesions in deciduous teeth

The purpose of this study was to evaluate the effect of the application of fluoride products on the development of enamel caries in deciduous teeth. A total of 108 deciduous teeth were chosen for the study. Acid-resistant varnish was applied on the teeth, leaving only one area of 5 mm x 1 mm of dental enamel exposed. The teeth were allocated randomly to one of the following groups: 1) control - toothpaste without fluoride; 2) 1.23% fluoride gel; 3) Duraflur fluoride varnish; 4) Duraphat fluoride varnish; 5) Fluorniz fluoride varnish; 6) Fluorphat fluoride varnish; 7) varnish with Duofluorid; 8) 12% silver fluoride diamine (Cariestop); 9) children's fluoride toothpaste (500 ppm). The tested products were applied on the teeth according to the manufacturer's recommendations and the teeth were stored in a moist environment for 24 hours. Each group of teeth was then subjected to a pH cycling model for 14 days, after which the teeth were cut through the center for an analysis of the depth of the carious lesion by polarized light microscopy. Comparisons were made between the treatments and the control group. The mean lesion depth values were 318 &#956;m ± 39 (control), 213 &#956;m ± 27 (fluoride gel), 203 &#956;m ± 34 (Duraflur), 133 &#956;m ± 25 (Duraphat), 207 &#956;m ± 27 (Fluor-niz), 212 &#956;m ± 27 (Fluorphat), 210 ± 28 (Duofluorid), 146 ± 31 (Cariestop) and 228 ± 24 (fluoride toothpaste). None of the products used here was able to completely prevent the formation of lesions. The highest cariostatic effect was achieved by fluoride varnish Duraphat and the lowest by the fluoride toothpaste