Thesis (M.Sc.) - Cairo University - Faculty of Oral and Dental Medicine - Department of Prosthodontics

Aim of the present study was to evaluate the effect of internal surface treatment by hydrofluoric acid and silane and external surface treatment by hydrofluoric acid, silane, stain and glaze application on biaxial flexural strength of enamic hybrid ceramics. A total of sixteen disc shaped samples of enamic hybrid ceramic (8 mm in diameter and 2 mm in thickness) were designed and milled using CEREC 3 CAD / CAM system. The samples were classified into four groups according to type of surface treatments, Group I: no surface treatment (control) (n = 4), Group II: External surface treatment (n = 4), Group III : Internal surface treatment (n = 4) and Group IV: Both internal and external surface treatments (n = 4). All samples were polished and then cleaned ultrasonically in distilled water. The biaxial {uFB02}exural strength was measured by the piston on three ball test in a universal testing machine. Data presented as mean and standard deviation (SD). Independent t-test and one way ANOVA was used. The significance level was set at P {u2264} 0.05. Both external and internal surface treatments group(IV) showed highest flexural strength (128.44 ± 3.74 MPa). External surface treatment group(II) (124.67 ± 5.78 MPa) showed the higher significant mean biaxial flexural strength (MPa) compared to Internal surface treatment group (III) (100.11 ± 22.22 MPa) and control group (I) (84.97 ± 4.3 MPa) at p = 0.001. Both external and internal surface treatment of hybrid ceramics affect its flexural strength .Glaze and stain were considered as important surface treatments step to optimize strength of hybrid material

Issued also as CD