Objectives:

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.

Methods:

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.

Results:

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).

Conclusions:

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.

Name of journal in which the research was published:

Damascus University Journal.

Publication Date:

2017.

Link: 

Damascus University Journal