Aim: To investigate the pulp chamber penetration of bleaching agent in intact teeth and teeth following restorative procedure.Methodology: Sixty extracted human incisors were selected and divided into 6 Groups. Four Groups were restored with hybrid composite resin and resin modified glass ionomer cement respectively, while 2 Groups were left intact. The Groups were then immersed in the treatment agents for 60 mins at 37°C. The optical density of the resultant blue solution obtained by adding leucocrystal violet and horseradish peroxidise to the acetate buffer solution present in the pulp chamber was measured spectrophotometrically and the data thus obtained was statistically analysed using ANOVA and paired t-test. Results:The amount of pulpal peroxide penetration in restored teeth was significantly higher than intact teeth (p< 0.001). the control Group showed no peroxide penetration. Groups restored with resin modified glass ionomer cement showed higher pulpal peroxide levels than Groups restored with hybrid composites, though the difference was not statistically significant (p = 0.52). Conclusion:Peroxide readily penetrates into the pulp through intact and restored teeth, with restored teeth showing higher pulpal peroxide levels than intact teeth. Teeth restored with resin modified glass ionomer cement showed higher pulpal peroxide level than teeth restored with composite resins.