Effect of Aging on the color stability of bleached shade resin composite (invitro)

Background and Aim: One of the most noticeable problems of composite restorations is color change of them over the time Due to this the most important advantage of composites which is providing esthetic is gone, so restorations need to be changed.The purpose of this   study is to evaluate the effect of aging on color stability of two types of  Bleached shade composites. Materials and methods: In this in vitro study 10 disk shape samples of each two  nanohybride composit es   DBl XL( IPS Empress Direct,Ivoclar Vivadent, Schaan, Liechtenstein)  and Ebl L( IPS Empress Direct,Ivoclar Vivadent, Schaan, Liechtenstein    in same size werefabricated.The primary color assessment was done by spectrophotometer matched which CIEI*a*b.Samples were done by the 10000 cycles of aging process which was equal to 1 clinical year. and then had the final test with her spectrometer. The results were evaluated with one way Anova. Results: the color change wasn’t perceptible( p=0.136)   ,while the difference in a* parameter between composites was perceptible and DBI was more than EBI.( p=0.000) The differences of b and ΔE parametres were not significant for two evaluated composites (p=0.377 and 0.136, respectively)   Conclusion: .The color change of bleached shade enamel and dentin resin composites after aging was acceptable clinically. (ΔE ≥  3/3)