Figure 2. FT-Raman average spectra of mineral components in the 400-1.080cm^-1 region showing phosphate peaks v 2 (431—449cm^-1 and v4, 582-611cm^-1) and carbonate peak v 3 (1070 cm-1) of demineralized enamel before (C, HP, HPF and HPC) and after (Cb, HPb, HPFb and HPCb) bleaching. It can be noted that after bleaching, all groups tested increased phosphate ( v 2 and v4) and carbonate ( v 3) inorganic contents of enamel.