Effects of Different Fluoride-containing Toothpastes on <i>In Vitro</i> Enamel Remineralization

Abstract

Fluoride toothpaste is one of the most effective cariostatic product when used as a daily fluoride application. The purpose of this in vitro study was to evaluate the effect of a new fluoride-containing toothpaste on enamel surface microhardness (SMH) under a pH-cycling regimen. Methods: Thirty-five sound human enamel samples were randomly divided into five groups (A-E) each containing seven samples as A (fluoridefree control group), B (1000 ppm NaF), C [KNO 3 (5%), 1450 ppm NaF], D (1450 ppm sodium monofluorophosphate), and E (1450 ppm NaF). After inducing caries-like lesions, each group was maintained daily for de-and remineralization cycle for seven days. During this cycle, samples were treated by the selected toothpaste for each group. Enamel mineral loss was assessed by SMH and lesion depth was analyzed by polarized light microscopy (PLM). Surface enamel microhardness was determined on the enamel blocks. SMH recovery (%SMHR) among treatments was analyzed by a two-way ANOVA. Results: The highest values of %SMHR were observed for the 1450 ppm NaF (group C). NaF toothpastes significantly increased the microhardness of the lesions (p<0.001) when compared to control groups. PLM data revealed a mineral precipitation band on the surface layer of all samples but no difference was found between groups in terms of enamel remineralization layers (p>0.05). The results suggest that all toothpastes with similar sources/concentrations of fluoride, provide different levels of remineralization. Conclusion: It can be concluded that new NaF compounds in toothpaste result in a clearly marked remineralization of caries-like enamel lesions.

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“…Concentrations of sodium molybdate were closed to mimic the proven concentrations of sodium fluoride in the prevention of dental caries and to ease the comparison between their means before and after. Regarding sodium fluoride, the results of the current studies were in agreement with several studies [21][22][23].…”

“…Concentrations of sodium molybdate were chosen to mimic the proved concentrations of sodium fluoride in prevention of dental caries to ease the comparison between their means before and after measurements. Regarding sodium fluoride results of current study were in agreement with several studies [22][23][24][25]. Table 6 demonstrates the significant differences between both solutions with that of deionized water which was used as a control (P< 0.000).…”

“…Statistically, data of results of this study showed significant differences between the initial and final measurements for all groups of enamel samples, the interpretation of these differences was due to differences in mineral contents in dental enamel and their distribution in different areas in the same tooth. Measurement was done under a load of 100 g which considered the least load was found to be necessary to obtain a well-defined indentation in the Vickers instrument; this load depended on the physical property of dental enamel, so this small load was used to avoid the plastic strain of enamel when dental enamel microhardness was measured as explained by a previous study [22][23][24][25]. As revealed in this study, demineralization was responsible for the reduction of microhardness values before the application of molybdenum solutions due to the loss of minerals by the action of acid in the demineralization solution, and as shown in this study, it was provoked by the application of different concentrations of molybdenum solution by increasing of the microhardness values after demineralization.…”

“…Subsurface artificial caries lesions were induced in each slab by immersion of these specimens for 24 hours at 37 °C in demineralization solution (pH 5.0), which consisted of 13 ml of 0.1 M lactic acid with 0.2% water-soluble resin (Carbopol C907; BF, Goodrich Chemical Co. Chemical division, 6100 Oak Tree Blvd. Cleveland, Ohio, USA) and, 50% saturated hydroxyapatite solution at pH 5.0 according to Torrado et al [22], and then examined under a polarized microscope (100 X). After that slabs were treated with a repeated schedule by exposing them for one minute to 0.025%, 0.075%, 0.150%, and 0.250% sodium molybdate prepared by serial dilution by constant stirring, followed by exposure to saliva for 29 minutes, and then immersed in mineralization solution for six hours without stirring, followed by rinsing with deionized water.…”

Knowledge and Attitudes of Pregnant Women with and without Children about Fluoride and Herbal Toothpastes

“…While there is substantial literature on the caries-preventing and remineralizing effects of fluoride (10)(11)(12), questions remain about its potentially unfavorable impact on the pineal gland, dental fluorosis, and mental retardation in children (13,14). However, these side effects usually occur after systemic and excessive fluoride intake (13).…”