EFFECT OF DIFFERENT FINISHING/POLISHING PROTOCOLS ON FATIGUE strength AND WEIBULL MODULE OF DIFFERENT ZIRCONIAS CERAMICS
Dental prosthesis; Ceramic; CAD/CAM; Adhesion
Objective: To evaluate the effect of different finishing/polishing protocols on the fatigue strength of new generations of zirconia. Materials and Methods: One hundred and eighty (N=180) ceramic discs will be made (Ø:12mm; 1,5mm-ISO 6872), 60 of ultra-translucent zirconia (UT-VITA, Vita Zahnfabrik ), 60 of a 3Y-TZP and 5Y-TZP multi-layer zirconia ceramic with translucency gradient (GT- e.max Zircad prime GT, Ivoclar) and 60 of ultra-translucent ceramic discs 4Y-TZP and 5Y-TZP multilayer zirconia (Nex- NexxZr+ multi, Sagemax Bioceramics). After the ceramic discs sintering, they will be divided into 12 groups (n=15), according to the factors “ceramic (UT, GT and Nex)” and “Finishing and polishing protocol” (Diamond burs + Rubbers; Diamond + Rubbers + Glaze; Rubbers and Control). The discs will be subjected to the fatigue resistance test by the stepwise method (5Hz for 10,000 cycles) with a step increment of 50N starting at 100N and continuing until failure. Two samples from each group will be prepared for topographic analysis in Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Atomic Force Microscopy (AFM) and fractograph analysis. The results will be statistically evaluated using 2-way ANOVA, Tukey test (5%) and Weibull analysis.