Discolored vital teeth have been effectively bleached with 10-20 percent carbamide peroxide bleaching materials. Objective: This double blind study examined two 30% carbamide peroxide tray bleaching materials used for one hour per day for ten days. Methods: Subjects were screened to ensure that initial tooth shade were Bioform shade guide 65 or darker. After obtaining consent, subjects were divided into two groups (n=20) at random. Custom-fabricated bleaching trays were made for each subject. Trays did not extend onto the gingiva. Each subject was instructed in the placement and wear of the tray and bleach. Each subject was supplied with the material- either A or B. Patients had 10 hours of contact with the bleaching gel. Used bleaching gel containers were returned at the end of the study to measure the amount used per patient. Photographs and shades were taken at baseline and at final recall. Tooth sensitivity was measured by applying a pellet saturated with skin refrigerant to the tooth for 2 seconds. The sensitivity was recorded on a visual analogue scale ranging from 1 to 10. Gingival index was measured at baseline and at the end of the study. Shade changes were measured using shade guides. Results: ANOVA for Repeated measures and Wilcoxon rank-sum test revealed that the final color change for the two concentrations of bleaching agent were the same (p=0.899), however more of the “B” material was worn compared to the “A” bleaching material. Cold sensitivity was transient and equal in both groups. Conclusions: 30 percent carbamide bleaching materials are effective home bleaching agents when worn for one hour per day. Higher concentrations of bleach may shorten bleaching time.