A Comparative Evaluation of Chemically Activated, Light-activated and Laser-activated Tooth Bleaching Systems

Background: Tooth bleaching systems can be classified as chemically activated, light-activated and laser-activated depending on activation mechanism. There is no unanimity of opinion with respect to the whitening efficacy and effect on enamel surface texture of these three types of systems. So, the present study was carried out to comparatively evaluate their whitening efficacy and effect on enamel surface texture. Materials and methods: Thirty-three extracted human anterior teeth were stained using coffee decoction for 7 days. Pre-bleaching color was evaluated with VITAPAN classical shade guide and a spectrophotometer. Samples were divided in three groups of 11 each namely: group I—chemically activated, group II— light activated, group III—laser activated. Post-bleaching color was evaluated with the same previous methods and difference in color preand postbleaching, dE, was calculated. Three samples, one per group, were subjected to scanning electron microscopic (SEM) evaluation both preand post-bleaching to study effect on enamel surface texture. Half the labial surface of these samples was covered using polytetrafluoroethylene tape so that half the surface was bleached and remaining half was unbleached acted at control. Photomicrographs were obtained preand post-bleaching. Results: Clinically, improvement of color was observed in all three groups. On statistical analysis, there was significant difference in dE between group II and III. On SEM evaluation, laser activation produced minimal effects on enamel surface texture. Conclusions: It was found that laser activated system was more effective in terms of whitening efficacy and it produced least effect on enamel surface texture.