[In vitro study of the effects of 10-30 % hydrogen peroxide solutions on the surface of human tooth enamel].

The aim of the present study was to investigate the effects of hydrogen peroxide solutions (10-30%) on the enamel surface and the inner structure of human teeth. Prepared enamel samples were exposed to various concentrations of hydrogen peroxide solutions for one hour. Changes in the enamel were analyzed by two different methods. The inner structure was studied by the Ellman's reagent to detect possible changes in the amount of free thiol groups in the remaining organic phase of matured enamel. Surface alterations were imaged by atomic force microscope. Ellman's reaction revealed the presence of three groups of free thiols: one with easy, the second one with medium and the third one with difficult accessibility by hydrogen peroxide. Atomic force microscopy revealed severe alterations on the enamel surface after treatment with both low and high concentration of hydrogen peroxide. Our observations indicated that hydrogen peroxide induced alterations in the surface structure and in the inner phases of mature enamel in both low and high concentrations.