Effect of a toothpaste containing titanium tetrafluoride and chitosan on enamel and dentin demineralization in an in vitro microcosm biofilm model.

OBJECTIVES: This study evaluated the anticariogenic effect and antibacterial activity of a titanium tetrafluoride (TiF4)/chitosan (Ch) toothpaste on enamel and dentin demineralization in an in vitro microcosm biofilm model. METHODS: Microcosm biofilm was produced from human saliva mixed with McBain saliva (0.2% sucrose) on bovine enamel and dentin for three days (5% CO2, 37°C). The treatments were applied as slurry (1 × 60 s/day): 1) TiF4/Ch (1400 ppm F⁻, 0.5% chitosan, 75% deacetylation, 500 mPas, pH 4.5); 2) TiF4 (1400 ppm F-, pH 4.5); 3) Ch (0.5% chitosan, 75% deacetylation, 500 mPas, pH 4.5); 4) Elmex® Caries Protection (GABA, Switzerland, 1450 ppm F- as AmF, pH 4.5, positive control); 5) placebo (pH 7.0, negative control); and 6) phosphate-buffered saline (PBS, pH 7.2). Colony-forming units (CFU) count was performed for total microorganisms, Lactobacillus spp., and Streptococcus mutans/S. sobrinus. Demineralization was measured by transverse microradiography (TMR). Data were compared using Kruskal-Wallis/Dunn test (p < 0.05). RESULTS: In enamel biofilm, TiF4/Ch significantly reduced Streptococcus mutans/S. sobrinus compared to placebo, whereas in dentin biofilm, this effect was observed only for TiF4 alone compared to both placebo and PBS. In enamel, TiF₄/Ch showed the lowest values of the integrated mineral loss (ΔZ) and lesion depth (LD), differing from Chitosan, Placebo and PBS groups. In dentin, similar performance was found for TiF4 and Elmex® on ΔZ, but not on LD (Elmex® was similar to placebo). No performance difference was observed between TiF4 and TiF4/Ch under this model. CONCLUSIONS: In conclusion, toothpastes containing TiF4 were able to reduce enamel and dentin demineralization in an in vitro microcosm biofilm model. CLINICAL RELEVANCE: TiF₄/Ch toothpaste reduced enamel and dentin demineralization under the present in vitro model, supporting its anticaries potential.