Crestâ Whitestrips bleaching strips provide unit dose applications of peroxide for safe and effective tooth bleaching.  Objectives:  This study examined the effects of Crest Whitestrips Supreme (CWSS) bleaching strips containing 14 % hydrogen peroxide on the surface integrity of human enamel and root dentin.     Methods:  Human enamel and root dentin blocks were sectioned and mounted in methacrylate.   Enamel was polished to a mirror finish with gamma alumina while dentin was prepared with 300 grit smear layer polish.  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 CWWS for 42 hours of treatment in a cycling regimen including continuous pooled saliva immersion with bid ½ hour treatments in peroxide gels.    A control group (CTR) was untreated and cycled through saliva soaks.   Following 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:  CWSS_I=349±21-nsd-CWSS_F21d=354±13;  CWSS_I=350±15-nsd-CWSS_F42d=356±12.  VHN measurements for dentin:  CWSS_I=56.2±1.8-nsd-CWSS_F21d=56.0±1.4;  CWSS_I=56.5±5.5-nsd-  CWSS_F42d=56.0±5.8.  Surface morphology of enamel and dentin were not influenced during bleaching.  Conclusions:  CWWS bleaching did not soften or etch surface enamel or root dentin, supporting the safety of this unit dose applied bleaching to oral hard tissue surfaces.