Background To evaluate the efficacy of fluoride-containing toothpastes with different technologies to remineralize artificial caries lesions in enamel. Methods Bovine enamel blocks were divided into three thirds: intact (untreated), demineralized (artificial caries lesion), and treated (caries lesion, pH cycling with dentifrices). Enamel blocks were randomly distributed into five groups (n = 12): Fluoride-free toothpaste, Colgate Oral Care (NC); Arginine-containing toothpaste, Colgate Total Daily Repair (PC); Silicate-based fluoride toothpaste: REFIX technology, regenerador + sensitive (RDC), NR-5 technology, Regenerate Enamel Science (RES), and NOVAMIN technology, Sensodyne Repair and Protect (SRP). The specimens were submitted to a pH cycling model for 6 days. The efficacy of the toothpastes was estimated by calculating the surface microhardness recovery (%SMHR) and the fluorescence recovery (ΔFRE) with quantitative light-induced fluorescence. The cross-sectional micromorphology of the enamel surface was also assessed using scanning electron microscopy. Elemental analyses (weight%) were determined with an energy-dispersive X-ray spectrometer (EDS). The results were compared to that of the control (NC). Data were statistically analyzed (5%). Results %SMHR could be ranked as follows: RDC = PC = RES = SRP > NC. Significantly higher %SMHR and ΔFRE means were observed after enamel treatment with RDC (22.7 and 46.9, respectively). PC (%SMHR = 18.8) was as efficacious as RDC to recover the surface microhardness with a significantly lower mean of ΔFRE (19.5). Only RDC was able to promote the formation of a mineralized layer on the surface of enamel enriched with silicon on the surface. Conclusions The silicate-based fluoride toothpaste containing REFIX technology demonstrated greater efficacy in the remineralizing artificial caries than the other products.

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The aim of this in vitro study was to evaluate the influence of treatment time on the remineralization performance of nanoencapsulated fluoride dentifrices on initial carious lesions. Ninety-six human enamel samples were allocated to eight groups (n = 12): 50% NanoF + 50% free NaF, 100% NanoF, 100% NaF (positive control), and placebo (negative control), using two different treatment times (one and five minutes) for each dentifrice tested. After the carious lesion induction, the specimens were submitted to a pH remineralizing cycling model for seven days. Surface microhardness was measured before and after carious lesion induction and after treatment. The percentage of surface remineralization was calculated for each study time. Data were analyzed using two-way ANOVA and ANOVA repeated-measures tests followed by the Bonferroni correction (p < 0.05). Remineralization differences were observed in the dentifrices analyzed according to the treatment time used. NanoF formulations with 50% (one-min treatment) and 100% (five-min treatment) promoted significant remineralization of enamel after the caries challenge when compared to the placebo dentifrice (p < 0.05). Thus, time was considered an important factor for the fluoride release system. Nanotechnology can be a promising system for caries remineralization as it makes fluoride available on the dental surface for a longer time.

Aim: To evaluate through an in vitro study surface changes on decayed enamel after the use of fluoridated dentifrices involving nanoencapsulated technology (NanoF). Methods: Forty blocks of human enamel were distributed among four groups (n = 10): 50% NanoF + 50% NaF (50% nF), 100% NanoF (100% nF), 100% NaF as the positive control (PC) and without fluoride as the negative control (NC). The specimens were subjected to a pH cycling model for 7 days. Surface microhardness (SMH), linear surface roughness (Ra) and area surface roughness (Sa) were measured before and after the carious lesion formation and at the end of the treatment. Percentages of surface microhardness recovery (%SMHR), altered Ra (%RaC) and altered Sa (%SaC) were calculated. The data were analyzed using the ANOVA test, repeated-measures ANOVA and Pearson's correlation test (p<0.05). Results: No significant differences among groups were found for Ra, Sa, %RaC or %SaC (p>0.05). Ra and Sa increased after treatment. A significant correlation was found between Ra and Sa. The PC dentifrice had the highest %SMHR, followed by 100% nF (p<0.05). In contrast, no surface remineralization was found in the 50% nF and NC groups. Conclusion: Enamel surface changes were found after the remineralizing treatment with 100% nF group. The majority of dentifrices with fluoride provided an increase in the roughness and surface microhardness. Nanotechnology is an innovative, promising method for the controlled release of fluoride and the remineralization of teeth with dental caries.