Dr. Ahmed Elmarakby has completed his PhD at the age of 38 years then postdoctoral studies both were from Al-Azhar University Faculty of Dentistry, Cairo, Egypt. He is Assistant Professor of restorative dentistry science, Alfarabi Colleges, KSA. He is A Lecturer in Operative Dentistry Department , Faculty of Dentistry,Al-Azhar University, Egypt. He has published 4 papers in international journal.He sheared one poster in the KSA at jan 2017 and has acceptance to 6 posters in 6 international conferences at this year 2017.

Abstract:This study evaluated four methods for discoloration removal from composite resins; 1-finishing with Sof-lex disks, 2-using pumice and polishing brush, 3-home bleaching technique using 10% carbamide peroxide and 4- chair side bleaching technique using 38% hydrogen peroxide.\r\n\r\nMaterials and methods: A total number of 60 composite disk specimens were prepared. Specimens were divided into 3 groups (n=20) according to the type of composite restoration used: Renamel, microfilled composite resin (Cosmedent, Chicago, IL, U.S.A.), Filtek Z250, micro-hybrid (3M/ESPE), and Nanocluster Filtek Supreme, Nanomer (3M/ESPE)and Renamel Then every main group were farther subdivide into 4 subgroups according to the type of method of discoloration removal that would use later (n=5). Specimens were immersed in a staining solution for 3 weeks. The stained surfaces of five specimens from each RBC material were treated with one of the treatment procedures. Colorimetric measurements were taken using spectrophotometer prior to and after staining, and then repeated after surface treatments. Color difference values were calculated using One-way ANOVA, Two-way ANOVA and Tukey’s Post Hoc tests.rn