Evaluation of the effect of four different bleaching strategies on pulp chamber temperature increase and microhardness changes of enamel surface

Abstract

Office bleaching is widely used for whitening the teeth and removing the toot discolorations .Although the efficiency of different methods has been evaluated, depending upon the technique used some pulpal hurts and surface hardness changes has been shown. The aim of this study was to evaluate the temperature of pulp chamber and enamel surface microhardness following four different bleaching strategies. Method and material: In this study 68 single root tooth were used. The crown section as removed using diamond disk. Pulp chamber was cleaned and prepared by gates glidden bur for easy placement of thermocouple. The teeth were randomly divided to four groups and different bleaching strategies were performed.G1: bleaching with 35% HP bleaching gel, G2: bleaching with 35% HP bleaching gel and LED, G3: bleaching with 35% HP gel and Nd:YAG laser, G4:bleaching with HP35% bleaching gel mixed with graphite particles and Nd:YAG laser. During the bleaching process temperature rise and microhardness changes was evaluated. Data was analyzed using SPSS software and proper post hoc analyses. Results: Results showed that in all groups there is a significant temperature rise. The difference was significant between LED and Nd: YAG groups. In all groups surface microhardness reduced significantly. Conclusion: Pulp temperature rise was significantly different in different groups. All of the techniques made the enamel surface hardness decrease