Evaluation of enamel microhardness after power bleaching by diode laser and LED with different bleaching gels

Objective: In-office bleaching is a technique that uses hydrogen peroxide based gels with an approximate concentration of 35%.The microhardness test is used as a method to evaluate the demineralization process. Since the introduction of in-office bleaching treatments, the application of different lights has been recommended to accelerate the process, and laser energy is a relatively new technique for tooth whitening; the aim of this study was to evaluate enamel microhardness after power bleaching by diode laser and LED with different bleaching gels Methods: In this experimental study, 36 human extracted intact premolar teeth were selected and randomly divided into three groups of 12 each (n: 12).Group 1: WhiteSmile hydrogen peroxide gel and Monitex LED (640 nm) with high intensity blue&red light, Group 2: DrSmile hydrogen peroxide gel and diode laser (980 nm) with power 2W and continuous wavelength and Group 3: Opalescence Ultra Boost hydrogen peroxide gel used according to the manufacturer?s instructions. Samples were subjected to the Vickers microhardness test (VHN) at a load 200 gr for 10s before and after treatment. Morphological changes assessed by scanning electron microscope (SEM). Data were statically analyzed by Repeated Measure ANOVA and Pos hoc Tukey. (p?0.05) Results: In all groups of this study except the LED group there was a significant reduction in enamel microhardness after bleaching process. (P: 0.012) .Tukey post hoc test showed that the average enamel microhardness in the Boost group was significantly different from the DrSmile group ;( p: 0.00) meaning that the amount of VHN after bleaching in the Boost group was less than DrSmile group. Conclusions: Due to the limitations of this study, it seems that power bleaching with WhiteSmile whitening gel and Monitex LED in the clinic has better results in terms of enamel microhardness than Boost and DrSmile bleaching gels.