Shear bond strength of veneering porcelain to zirconia: Effect of surface treatment by CNC milling and composite layer deposition on zirconia.
OBJECTIVES The purpose of this study was to evaluate the shear bond strength of veneering feldspathic porcelain to zirconia substrates modified by CNC milling process or by coating zirconia with a composite interlayer. METHODS Four types of zirconia porcelain interface configurations were tested: RZ porcelain bonded to rough zirconia substrate (n=16) PZ porcelain bonded to zirconia substrate with surface holes (n=16) RZI application of a composite interlayer between the veneering porcelain and the rough zirconia substrate (n=16) PZI application of a composite interlayer between the porcelain and the zirconia substrate treated by CNC milling (n=16) The composite interlayer was composed of zirconia particles reinforced porcelain (30% vol% The mechanical properties of the ceramic composite have been determined. The shear bond strength test was performed at 0.5mm/min using a universal testing machine. The interfaces of fractured and untested specimens were examined by FEG SEM/EDS. Data was analyzed with Shapiro Wilk test to test the assumption of normality. The one way ANOVA followed by Tukey HSD multiple comparison test was used to compare shear bond strength results (a=0.05) RESULTS The shear bond strength of PZ (100+ 15MPa) and RZI (96+ 11MPa) specimens were higher than that recorded for RZ (control group) specimens (89+ 15MPa) although not significantly (p>0.05) The highest shear bond strength values were recorded for PZI specimens (138+ 19MPa) yielding a significant improvement of 55% relative to RZ specimens (p<0.05) SIGNIFICANCE This study shows that it is possible to highly enhance the zirconia porcelain bond strength even by ~55% by combining surface holes in zirconia frameworks and the application of a proper ceramic composite interlayer.
Journal of the mechanical behavior of biomedical materials