Temperature rises during tooth bleaching with different light-curing units

The aim of this study was to evaluate the influence of three different light-curing units on the temperature rise induced in the pulpal cavity, when bleached with 35% hydrogen peroxide (HP). Forty extracted maxillary central incisors were randomly divided into four groups according to photoactivation procedure (n = 10). Whiteness HP (WHP) bleaching agent which contains 35% HP bleach was placed on the facial tooth surface and no photoactivation device was used (control); an blue light-emitting diode (LED, 40 s), a diode laser (4 W, Continous mode, 20 s), and Nd:YAG laser (4 W, 60 Hz frequency, 20 s). Temperature rise in the pulpal chamber was measured with a J-type thermocouple wire that was connected to a data logger before and immediately after each 20–40 s application. One tooth of each group was selected for scanning electron microscope analysis. Data were analyzed using one-way ANOVA followed by the Games Howell post hoc test at a preset α of 0.05. One-way ANOVA revealed that there was a significant d...