The aim of this clinical study was to evaluate tooth color relaps after exposure to different whitening methods using several materials (hydrogen peroxide 7.5%, carbamide peroxide22%- which gives 7.5%of hydrogen peroxide – carbamide peroxide 45% using its two methods of application.
20 subjects (240 upper and lower anterior teeth) were distributed into 4 groups ( 60 teeth were submitted to 45-min exposure of cp 22% daily for 14 days . 60 treated with 45-min daily of hp 7.5% for 14 days, 60 treated with 3 exposures of 45- min of cp 45%, 60 were submitted to combined treatment of one exposure to cp 45% and 45 min exposure daily to cp 22% for 7 days . instrumental color measurements were obtained from teeth 14 days and 12 months after bleaching using Vita easyshade compact. color change ΔE was calculated using this equation ∆E= [(∆L*)2 + (∆a*)2 + (∆b*)2]1/2 Data were analyzed using ANOVA test to study statistically differences among 4 groups, and t test to study differences between upper and lower jaw.
there was no statistically significant difference among the four whitening groups ( p=0.07), ΔE ranged between 4.1 for FGM22% & 5.3 for Opalescence 45%. There was also no statistical differences between upper and lower jaw (p=0.77).
Within the limitations of this study, FGM22% showed the smallest relapse value whereas Opalescence 45% showed the largest relapse value . without statistically significant difference between upper and lower jaws for all studied groups.
Damascus University Journal.
2017.
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