Two in-office bleaching systems: a scanning electron microscope study

The purpose of this investigation was to analyze by scanning electron microscopy the effects of heated and light-absorbing bleaching agents on enamel surface morphology. Twelve freshly extracted human anterior teeth were selected for this study. The teeth were randomly divided into four equal groups: Group I (control), Group II (teeth treated with Opalescence Quick, a heated bleaching agent), Group III (teeth treated with Opalescence Xtra, a light-absorbing bleaching agent), Group IV (teeth treated with Ultra-Etch 35% phosphoric acid etchant). After receiving a prophylaxis with a slurry of pumice, the bleaching materials were applied to the facial enamel surfaces following the manufacturer's specifications. The teeth in Group IV were etched for 15 to 20 seconds, washed, and air-dried. All specimens were prepared for scanning electron microscope evaluations. Scanning electron microscope micrographs indicated that only those specimens etched with phosphoric acid (Group IV) exhibited an etching pattern on the enamel surface. No differences in enamel surface morphology were observed between the untreated control specimens and the specimens treated with the bleaching materials.