Optical Effects of Experimental Light-Activated Bleaching Procedures

Objective: The purpose of this study was to evaluate the efficiency of experimental light-activated bleaching procedures. Background data: The improved color effect may be attributed to the potential photochemical effect of light-emitting diode (LED405), organic LED (OLED), and femtosecond laser rather than to the photothermal effect of conventional lights used for tooth bleaching. Materials and methods: Specially made pastilles of hydroxylapatite were immersed in green tea for 8 h and randomly divided into four groups ( n =50) specified by the type of light source applied during a 30 min bleaching treatment: LED405, OLED, and femtosecond laser, or its absence (control group). Each group was treated with five bleaching gels: 10%, 16%, and 30% carbamide peroxide (CP), and 25% and 38% hydrogen peroxide (HP). Changes in color were determined by red–green–blue (RGB) colorimeter and ultraviolet-visible–near-infrared (UV/Vis/NIR) spectroscopy. Results: Regardless of the applied bleaching gel, LED405 produced a larger increase in the value of RGB index than did OLED and bleaching without light activation ( p