The effect of four different bleaching strategies on penetratration of hydrogen peroxide into the pulp chamber

Abstract

Office bleaching is widely used for whitening the teeth and removing the tooth 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 effect of four different bleaching strategies on penetration of hydrogen peroxide into the pulp chamber. Method and material: In this study 72 single root tooth were used.The samples were cut 2 mm beneath CEJ. Pulp chamber was cleaned and prepared by gates glidden bur for easy placement of accetat buffer. 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 35% HP bleaching gel mixed with graphite particles and Nd:YAG laser.To evaluate the penetration of hydrogen peroxide,the color intensity was measured by uv/visible spectrophotometer in wavelength of 596 nm and by using the standard calibrated curve the value for penetration of hydrogen peroxide was gained in microgram . Data was statistically analysed using SPSS software and variance analysis.For comparing between groups Tukey analysis in significant stage 05/0= was used. Results:Results showed that: 1- The penetration of hydrogen peroxide increased in 3 groups to control group. 2-The difference between the control group and laser,control and laser+graphit,laser and laser+graphit was significant.(p<.0001) 3-The difference between laser and LED was significant.(p=.015) 4-The difference between control and LED was not significant.(p=.099) Conclusion: The penetration of hydrogen peroxide increased in 3 groups comparing with control group but the difference is not significant between control and LED groups .