Hydrogen peroxide bleaching strips provide unit dose applications of peroxide for safe and effective tooth bleaching. Objectives: This study examined the effects of hydrogen peroxide bleaching strips containing 6.0 % hydrogen peroxide on the surface integrity of human enamel. Methods: Human enamel blocks were sectioned and mounted in methacrylate. Enamel was polished to a mirror finish with gamma alumina. Color determinations (CIELAB) of standardized areas on surfaces were taken by image analysis and surfaces were pre-measured for surface microhardness. Teeth were bleached with hydrogen peroxide bleaching strips (HPS) in a cycling regimen including continuous pooled saliva immersion with 4x/day 5 minute treatments in peroxide gels. An untreated control group included specimens which underwent no cycling (UCTR) while a second control group (CTR) was untreated and cycled through saliva soaks. All specimens were treated bid with slurries of Crest® Regular Formula NaF dentifrice (including a pretreatment period before bleaching). Following 120 treatments bleaching color values and surface microhardness were re-determined. Surface profilometry, SEM and air objective CLSM were used to confirm surface effects. Results: Colorimetric evaluations confirmed significant tooth bleaching for peroxide exposures. VHN measurements for enamel following 120 treatments: UTCL=366±24-nsd-CTR=366±23-nsd- HPS=359±19. Conclusions: HPS treatments did not soften or etch surface enamel supporting the safety of this unit dose applied bleaching to oral hard tissue surfaces.