It was observed that externally applied bleaching gels may penetrate into the pulp chamber. This study was conducted to evaluate the peroxide diffusion from two whitening strips into the pulp chamber. Twenty-four, human, extracted, maxillary central teeth were separated into three groups (n = 8). All teeth were sectioned 3-mm apical to CEJ, the intracoronal pulp tissue was removed, and the pulp chamber was filled with acetate buffer. Vestibuler crown surfaces of teeth in the experimental groups were subjected to whitening strips; the teeth in the control group were exposed only to distilled water. The acetate buffer solution in each tooth was transferred to the tube. Leuco-crystal violet and enzyme horseradish peroxidase also were added to the tube. The pulpal peroxide was determined spectrophotometrically. The results indicated that the whitening strip containing 14% hydrogen peroxide presented a higher pulpal peroxide penetration than 6.5 % hydrogen peroxide (p < 0.001).

The peroxides from the whitening strip and paint-on whiteners penetrated into the pulp chamber to varying degrees.

This work has focused on the effects of different hydroxypropylmethylcellulose (HPMC) types and HPMC:direct tabletting agent (DC-agent) ratio on Verapamil Hydrochloride (VRP HCl)