Abstract

Background: In this study, composite samples of four different types were exposed to carbamide peroxide 16 and hydrogen peroxide 40, and the results were compared with a control group. The aim of this study was to investigate color changes in a variety of composite materials after bleaching treatments and to compare them with one another. Materials and Methods: A total of 36 composite discs from each composite (Z100, Z250, Z350, P90) were prepared with dimensions of 3 mm × 8 mm. The aging process and staining of samples were done for 4 weeks, then specimens were placed on 5000 cycle in thermocycling device. The samples were numbered, and primary color of each specimen was recorded. Samples of each composite material were divided into two subgroups, 12 specimens each and each subgroup were exposed to different bleaching treatments: (1) Untreated control group and (2) carbamide peroxide 16 (home bleaching) and hydrogen peroxide 40. After 14 days of treatment, secondary colors and color changes were recorded accordingly. The data were analyzed by analysis of variance and Tukey, and a P = 0.05 was calculated. Results: The mean ΔE reported after treatment of home bleaching in composite Z100 (17.4), Z250 (21.1), Z350 (17.0), P90 (16.9) and after office bleaching treatment in composite Z100 (16.0), Z250 (21.1), Z350 (16.6), P90 (17.5) with difference from the untreated samples of Z100 (2.5), Z250 (2.8), Z350 (2.3), P90 (2.4). All composites were significantly brighter after bleaching treatments than the control group (ΔE >3.3). In our study, there was no significant difference between the effectiveness of different bleaching methods. Conclusions: Hydrogen peroxide and carbamide peroxide bleaching agents are effective in whitening of the discolored composite. These two treatments are not significantly different in terms of their effects. Among different composites, Z250 showed the greatest color change among all others.