This in vitro study evaluated the protective effect of an Si-containing toothpaste associated with different fluoride concentrations by reducing the depth of the demineralized lesions in dentin after cariogenic pH cycling. Methods: Sixty bovine dentin blocks (4 × 4 × 2 mm) were randomly assigned into five groups (n = twelve/group): RGS₁ (Si toothpaste with 1450 ppm F), RGS₂ (Si toothpaste with 1100 ppm F), RGS₃ (fluoride-free Si toothpaste), negative control (NC) (fluoride-free toothpaste), and positive control (PC) (1450 ppm F toothpaste). The specimens underwent a three-day pH cycling model simulating the oral environment with twice-daily brushing. The mineral loss (ΔF) and lesion depth (ΔF_max) were assessed using quantitative light-induced fluorescence (QLF), and scanning electron microscopy (SEM) provided a morphological analysis. Elemental analyses were performed with an energy-dispersive X-ray spectrometer (EDS). ANOVA and Tukey’s test were used for the data analysis (α = 5%). Results: EDS confirmed the Si in the toothpaste formulations. The groups treated with fluoride silicon toothpastes (RGS₁, RGS₂) had significantly reduced mineral loss and lesion depth compared to the PC group. The NC group exhibited the greatest mineral loss and lesion depth. SEM images revealed occluded superficial dentin tubules and a protective mineral layer in the groups treated with Si toothpaste, whereas no deposition (NC group) or limited mineral deposition (PC group) was observed in the control groups. Conclusions: The findings suggest that the Si toothpastes favored protection against dentin demineralization, even at a lower concentration or free of fluoride, with dentin tubule occlusion, thus representing a promising oral care product over traditional fluoride toothpastes.

This in vitro study evaluated the protective effect of a Si-containing toothpaste associated with different fluoride concentrations by reducing the depth of demineralized lesions in dentin after cariogenic pH cycling. Methods: Sixty bovine dentin blocks (4x4x2mm) were randomly assigned into five groups (n = 12/group): RGS1 (Si-toothpaste with 1450 ppm F), RGS2 (Si-toothpaste with 1100 ppm F), RGS3 (fluoride-free Si-toothpaste), negative control-NC (fluoride-free toothpaste), and positive control-PC (1450 ppm F toothpaste). The specimens underwent a three-day pH cycling model simulating the oral environment with twice-daily brushing. Mineral loss (ΔF) and lesion depth (ΔFmax) were assessed using quantitative light-induced fluorescence (QLF), and scanning electron microscopy (SEM) provided morphological analysis. Elemental analyses were determined with an energy-dispersive X-ray spectrometer (EDS). ANOVA/Tukey's test were used for data analysis (α = 5%). Results: The groups treated with fluoride silicon-toothpastes (RGS1, RGS2) significantly reduced the mineral loss and lesion depth compared to the PC group. The NC group exhibited the greatest mineral loss and lesion depth. SEM images revealed occluded superficial dentin tubules and a protective mineral layer in groups treated with Si-toothpaste, whereas no deposition (NC group) or a limited mineral deposition (PC group) was observed in the control groups. EDS confirmed Si in the toothpaste formulations. Conclusions: Findings suggest that Si-toothpastes favored protection against dentin demineralization even at a lower concentration or free of fluoride, with dentin tubule occlusion, thus consisting of a promising oral care product over traditional fluoride toothpastes.