Title: 0665 - Optical and Mechanical Properties of Different Zirconia Generations
Islam Abd Alraheam (Presenter)
University of North Carolina
Terence Donovan, University of North Carolina
Lee Boushell, University of North Carolina
Ryan Cook, University of North Carolina
Andre Ritter, University of North Carolina
Taiseer Sulaiman, University of North Carolina
Objectives: To evaluate the effect of fatiguing and thermocycling on bi-axial flexural strength and optical properties of different zirconia generations as a function of thickness.
Methods: Third generation fully stabilized zirconia (FSZ, 5-6 mol% Yttria) and first generation partially stabilized zirconia (PSZ, 2-3 mol% Yttria) (Bruxzir, Glidewell) were evaluated. Specimens (14 mm diameter discs) were prepared to different thicknesses: 0.7 mm and 1.2 mm from each zirconia type and according to ISO 6872. A total of 4 groups (n=16/group) are tested before (baseline) and after fatiguing to 1.2 million cycles at 100N load with simultaneous thermocycling 5-55°C (Chewing Simulator, SD Mechatroniks). Translucency parameter (TP), contrast ratio (CR) and light blockage percentage are recorded using a spectrophotometer before and after fatiguing and thermocycling. Data will be analyzed by two- way ANOVA.
Results: Baseline bi-axial flexural strength of PSZ was higher than FSZ at both thicknesses. Baseline ranking from most to least translucent according to TP and CR measurements: FSZ (0.7 mm), PSZ (0.7 mm), FSZ (1.2mm), PSZ (1.2mm). Higher light blockage percentage was recorded in PSZ groups, 62%, 56% at 1.2 mm, 0.7 mm thickness respectively. FSZ had 60.2%, 52.5% light blockage at 1.2mm, 0.7 mm respectively. The 0.7 mm thickness group were more translucent and had lower light blockage percentage than the 1.2 mm thickness group. Post-fatiguing and thermocycling mechanical and optical properties are being collected.
Conclusions: Different generations of zirconia according to yttria concentration display different mechanical and optical properties. Third generation FSZ is weaker and more translucent than the first generation PSZ.
The submitter must disclose the names of the organizations with which any author have a relationship, the nature of the relationship, and the clinical or research area involved. The following is submitted: None