The aim of this project is to evaluate in vitro and in vivo the effect of dental bleaching agents, carbamide peroxide 16% (T1) and hydrogen peroxide 35% (T2) together with desensitizers/remineralizer agents, Sensodyne® dentifrice (D1); experimental dentifrice with 7,5% of Biosilicate micro-particles (D2); Odontis RX® dentifrice (D3); Sorriso® dentifrice (D4); Biosilicate micro-particles paste, 1:1 (D5), Desensebilize Nano P (D6), bioglass type 45S5 paste, 1:1 (D7); GC= distilled water, in the experimental groups: T1/D1; T1/D2; T1/D3; T1/D4; T1/D5; T1/D6; T1/D7; T1/GC e T2/D1; T2/D2; T2/D3; T2/D4; T2/D5; T2/D6; T2/D7; T2/GC. In the in vitro study, microhardness and roughness measurements, and images using scanning electron microscopy (SEM) will be made on samples of bovine dental enamel and dentin (4x4x3mm; n=10 per group) before and after the treatment with the bleaching gels (T1= 14 days/ 04 hours/day; T2=single session) and the desensitizers/remineralizer agents. In the clinical study, the volunteers (n=10 per group) will be evaluated regarding dentin hypersensitivity (DH), using visual analogue scale, before the beginning of the treatments (T1 and T2) and during the next 14 days (1º, 3º, 7º, 10 º e 14º days) in which the desensitizers/remineralizer agents (there´s no control group in the clinical experiments) will be applying. Data will be analysed intra and inter-group, statistically.