Remineralization of enamel subsurface lesions using toothpaste containing tricalcium phosphate and fluoride: an in vitro μCT analysis

BackgroundThis study aimed to compare the efficacies of experimental toothpastes containing functionalized tricalcium phosphate (fTCP) with and without fluoride for in vitro enamel remineralization under pH-cycling conditions.MethodsTo create artificial white spot lesions, 36 bovine enamel specimens were immersed in a demineralization solution for 10 days. During pH-cycling for 12 days, the specimens were divided into four groups based on the experimental toothpaste type used: (a) fTCP-free, fluoride-free (fTCP-F-); (b) fTCP-containing, fluoride-free (fTCP+F-); (c) fTCP-free, fluoride-containing (fTCP-F+); and (d) fTCP-containing, fluoride-containing (fTCP+F+). Micro-focus X-ray computed tomography (mu CT) scans of all specimens were obtained before demineralization, after demineralization, and after pH-cycling. The mineral density and mineral loss (Delta Z) in the enamel subsurface lesions were measured and the percentage of remineralization (%R) was calculated from Delta Z after demineralization and pH-cycling. One-way ANOVA with Tukey's test was used for statistical analysis of the %R values. The treated enamel surface was investigated via scanning electron microscopy (SEM).ResultsThe fTCP-F-group presented with the lowest amount of mineral gain after pH-cycling. In contrast, the fTCP+F+group showed the highest degree of remineralization within all lesion parts. The %R was highest in the fTCP+F+group (38.27.8, all P<0.01). SEM revealed the presence of small crystals on the enamel rods in the fTCP+F-and fTCP+F+groups.ConclusionsThe experimental toothpaste containing fTCP and fluoride increased remineralization of the artificial enamel subsurface lesions during pH-cycling. Furthermore, fTCP and fluoride appear to act independently on the remineralization of enamel subsurface lesions, although they coexisted in one toothpaste type.Trial registration: This is not a human subject research.