In this research, the effect of three bleaching materials, 20% carbamide peroxide, 35% carbamide peroxide and 38% hydrogen peroxide on the solubility of enamel is examined. For this study, 30 premolar teeth extracted for orthodontic purpose were used. They were divided into three groups 10 teeth in each Crowns of the teeth were divided into 2 pieces longitudinally. One part of the tooth crown was used as control and the other part was used as experimental group. 20 percent carbamide peroxide was applied at 370 C during 6 hours for 8 days to the first test group (at-home bleaching), 35 percent carbamide peroxide was applied at 37 0C for 30 minutes for 8 days to the second test group (at-home bleaching) and 38 percent hydrogen peroxide was used 4 times for 15 minutes making a total 60 minutes on the remaining ten specimen (in-office bleaching). The solubility of the enamel was calculated by the determination of inorganic phosphorus using a spectrophotometer. Comparative analysis of the depths in the groups was carried out and its relation with mineral loss was evaluated. Paired t-test was used to compare the differences between the groups. A statistically significant difference was found between the control and the study groups for the 38% hydrogen peroxide. There was no statistically significant difference between the control and experimental groups in the other two groups. It is concluded that of these three bleaching materials, 38% hydrogen peroxide has the greatest effect on mineral loss from the enamel
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