Effectiveness of Fluoride Si-Toothpastes to Remineralize Dentin After pH Cycling

Objectives: 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 (ΔF_max) 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.