EFFECT OF BLEACHING AGENTS ON MICROHARDNESS AND SURFACE-MORPHOLOGY OFTOOTH ENAMEL

Purpose: To investigate the effects of three bleaching agents on ename l microhardness and surface morphology in vitro. Materials and Methods : The bleaching agents examined (Colgate Platinum, Nite White and Opal escence Mint) contain each 10% carbamide peroxide as the active agent. Surface enamel microhardness was measured with a Vickers diamond afte r standardization of the diamond indenter on the test surface and with the microscope reading of the indentation. Prepared enamel slabs from each group were evaluated on enamel surface morphology by SEM. Statis tical comparisons were carried out between the microhardness of the gr oups and the difference within the group. Results: The treatments decr eased the initial microhardness in the following order: Opalescence Mi nt < Colgate Platinum < Nite White, but without statistically signific ant differences. Erosion patterns were detected between the control su rfaces and the experimental surfaces of each group (Am J Dent 1998;11: 83-85).