RESUMEN
Esthetic dentistry and tooth esthetics are important parts of dental treatments today. Among these, Tooth bleaching treatment is a simple, safe and effective way to accommodate many patients' needs. Regarding to production of dental materials in Iran, this in-vitro study was conducted to compare the whitening effect and the speed of efficiency of bleaching agents [kimia 16% and Opalescence F 15%] using a tray. This experimental study was performed on forty extracted caries free maxillary central incisors which did not have any fluorosis and tetracycline discoloration. Roots of the teeth were covered with 2 layers of nail polish and they were divided into two groups then embedded in red wax. After preparing the bleaching tray for two groups, photographs of teeth were taken and the values of the teeth were determined visually using a vita shade guide. Afterwards the teeth were treated by carbamide peroxide gels [Kimia 16% and opalescence PF 15%] for an hour a day for two weeks. The lightness of the teeth were evaluated every day before treatment and also one month after the treatment period and the data was recorded. The data were analyzed by Signed T test, ANOVA and Mann-Withney U tests. The findings of this study showed that whitening effects of the two agents were statistically significant [P<0.01]. At the end of the study according to the recorded value, the lightness change in groups treated with Kimia was 6 degrees and in the other group [Opalescence PF], it was 6.3 degrees. There was no statistically significant difference between the two bleaching gels [P>0/05]. Using the tray bleaching method, both gels [16% Kimia and 15% Opalescence PF] had equivalent effects on whitening of the teeth