A scanning electron microscope study of the long-term effect of bleaching agents on the enamel surface in vivo.

Vital bleaching of teeth is, increasingly, a popular esthetic desire. Bleaching agents are provided in over-the-counter as well as dental office bleaching kits. However, the effect of the bleaching agents on the enamel surface is not fully understood, and cautions approaches to their use are not usually explained to patients. In this study, an in vivo exposure of bleaching agents is used to evaluate the short and long-term effect on the enamel surface; the results are demonstrated by scanning with an electron microscope. Exposure to the bleaching agents for 14 days created an alteration of the enamel surface and caused exposure of the enamel prisms. Moreover, a 21- to 90-day post-exposure SEM evaluation demonstrated alteration of the surface enamel, indicating exposure of the enamel prismatic layer, frequently to the depth of the enamel rods and possibly the dentin.