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Scanning Electron Microscopy Investigation Of Enamel Surface Treated With Different Bleaching Agents

Kemaloglu H,Atalayin C*,Tezel H

Introduction: Bleaching of the discolored teeth has gained popularity in the public, but there is little information about the effects of bleaching products on tooth surface. The aim of this in vitro study was to evaluate the effects of different bleaching agents with different concentrations and activation methods on enamel surface.
Materials and Methods: Human impacted third molars (n=5) were divided into six parts and the specimens obtained from each tooth were randomly assigned to one of the six groups. Group 1: No agent was used (positive control) Group 2: 10% Carbamide Peroxide (CP) Group 3: 25% Hydrogen Peroxide (HP) + mercury metal halide light activation Group 4: 38% HP + quartz-tungsten-halogen light activation Group 5: 38% HP + diode laser activation Group 6: 37% Orthophosphoric acid (negative control) The specimens were kept in artificial saliva during the test period and then prepared for scanning electron microscopy analysis. Photomicrographs of representative areas were taken at 5000x and 10000x magnifications.
Results: There were no remarkable morphologic alterations in Group 1. Bleached groups showed alterations on surface smoothness. A slight increase in the enamel porosity occurred in Group 2. The appearance was similar to the unbleached enamel in Group 3. Mild intraprismatic structure dissolution formed with the increased porosity and concavity in Group 4. Minor alterations on surface smoothness and mildly increased porosity occurred in Group 5. Rough and uneven surface, which indicated alterations of the prismatic structure of enamel due to selective dissolution of the apatite crystals, consisted in Group 6.
Conclusion: The activation methods that shorten the contact time of the high concentrated peroxides can be useful to avoid the alterations caused by bleaching agents.