Document Type : Original articles
                            
                        
                                                    Authors
                            
                                                            
                                                                            1
                                                                        Prosthodontics department, faculty of dentistry, badr university in cairo, cairo, egypt                                
                                                            
                                                                            2
                                                                        Associate Professor, Department of Fixed Prosthodontics, Faculty of Dentistry, Ain Shams University, Cairo, Egypt.                                
                                                            
                                                                            3
                                                                        Professor, department of fixed prosthodontics, faculty of dentistry, ain shams university, cairo,egypt                                
                                                            
                                                                            4
                                                                        Professor, Department of Fixed Prosthodontics, Faculty of Dentistry, Ain Shams University, Cairo, Egypt.                                
                                                            
                                                                            5
                                                                        Vice Dean, Postgraduate Affairs and Scientific Research, Faculty of Dentistry MIU, Egypt.                                
                            
                                                                            
                        
                        
                            Abstract
                            Aim: To evaluate the effect of speed sintering protocol and hydrothermal aging on the biaxial flexural strength of recent cubic zirconia material.
Materials and methods: Discs were prepared from recent cubic zirconia material, Katana UTML (K). The prepared discs were fabricated from milled cylinders. Prepared discs were divided according to sintering protocol applied, either a normal cycle (N) or a speed cycle (S). Half of the discs were subjected to biaxial flexural strength (BFS) test using a universal testing machine.the remaining discs were submitted to accelerated aging (A) for 5 hours and then subjected to biaxial flexural strength (BFS) test. Data collected and analyzed using one-way ANOVA. Scanning electron microscope was used for microstructure analysis. 
Results: Non-significant difference in (BFS) values were found between both normal and speed sintering protocols before and after subjecting to hydrothermal aging, The highest overall values were reported from KSA (2168± 212.4 MPa) . Average mean grain size values showed a reduction in size after subjecting to speed sintering protocol. 
Conclusion: Speed sintering protocols and hydrothermal aging did not report a significant difference in biaxial flexural strength mean values. Speed sintering cycles reduced the mean values of grain size.
                        
                        
                        
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