Mostafa Shahin Zaki , Cherif Adel Mohsen And Mostafa El Husseiny,

ABSTRACT
Aim Of The Study: To Assess The Flexuralstrength And Color Parameters Of The Two Different Translucent Zirconia Materials Namely Super Translucent Multi-layered Zirconia And Ultra Translucent Multi-layered Zirconia Compared To 3Y-TZP And Lithium Disilicate.

Materials and Methods: Hundred Disc Specimens (Diameter = 12mm, Thickness = 1.2mm) Were Divided In To Four Main Groups According To Type Of Ceramic Material As Ten For Monochromatic Ceramics BruxZir Zirconia Group And IPS E.max Group And Fourty For Multi-layered Ceramics Katana STML Group And Katana UTML Group. Groups Were Subdivided In To Ten Subgroups According To Layers Of Multi-layered Ceramic Materials (n = 10), Four Subgroups For Each Multi-layered Ceramic Material And One Subgroup Of Each Monochromatic Ceramic Material. Each Subgroup Was Subdivided In To Two Classes According To Degradation (n = 5), Where Firstclass Was Corrosion, While Second Class Was A Control Not Subjected To Corrosion. Spectrophotometer Measurement For Each Class, Then Flexural Strength Assessed For Same Specimens

Results: Corrosion Caused Significantweight Loss For All Materials With Greatest Value Measured For Both Katana STML And Katana UTML. Corrosion Caused Clinically Unacceptable Color Change For Katana STML And Katana UTML Compared To Other Materials. Corrosion Caused Significantincrease Of Bi-axial Flexural Strength Of BruxZir Specimens, However Didnt Affect Other Materials. Conclusion: Both Katana STML And Katana UTML Experienced Greater Solubility And Color Change Compared To Other Tested Ceramics. Regarding Flexuralstrength Both Katana STML And Katana UTML Were In Between BruxZir And IPS E.max CAD. Corrosion Affected BruxZir Specimens Only.