The present study aims 1) to evaluate the effect of 4% TiF4 varnish compared to 5.42% NaF and 2% chlorexidine on the prevention of dentin demineralization under a cariogenic microcosm biofilm and 2) to validate the use of Micro-CT to measure dentin demineralization. For the microcosm biofilm formation, saliva will be collected from 2 healthy subjects, who must have not brush their teeth for the last 24h and not drink or eat for the last 2h. The saliva will be diluted (70% saliva and 30% glycerol), and aliquots of 1 ml will be stored at -80ºC. Bovine root dentine samples (4 mm x 4 mm) will be prepared and treated for 6h with the varnishes containing: A) 4% TiF4 (pH 1.0, 2.45% F); B) 5.42% NaF (pH 5.0, 2.45% F); C) placebo D) 2% chlorexidine gel - positive control or E) untreated - negative control (n=16). The dentin samples will be exposed to human saliva mixed with McBain saliva (1:50) containing 0.2% sucrose (v=1.5 ml) for the microcosm biofilm formation, using 24-wells plates for period that will be defined (pilot study with 5, 10 and 15 days). The dentin demineralization will be measured using Micro-CT, at the University of Göttingen, GER and using transverse microradiography-TMR at the University of São Paulo, BR. The data will be plotted and submitted to the statistical analysis (p<0.05).
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