Evaluation of phisical changes of CAD/CAM materials after function

Purpose: The most important disadvantage of ceramic materials had been used in dentistry, is their low physical resistance. Nowadays, newly develped all ceramic materials are up for sale on the market, which have significantly improved physical properties. This study aims to investigate comparatively the fracture and wear strength of crown prosthesis which are prepared by recently developed CAD/CAM materials. Material and Method: 30 pieces of digitally designed and milled lower 1st molar teeth prepared by dentin likeVita CAD-Temp discs. The prepared teeth were divided into groups consisting of 10 specimens and crown prosthesis were prepared by 3 different CAD/CAM blocks IPS e.max CAD, Vita Enamic, inCoris Zirconia. All of the crown restorations are cemented on dentin like prepared composit dies by usingRelyX U200 resin cement material under static 50N pressure. Samples are loaded for wear test at 1.7Hz to 106 cycles under 5°-55°C termal cycle. After the wear test all survived samples were applied to fracture test. Fractured samples are grouped according to Burke classification. Most frequently observed fracture type of each group is examined under electron microscope (SEM). Results are analyzed by one-way analysis of variance (ANOVA) and Turkey HSD test. Results: The statistical analysis revealed that the lowest wear values and highest fracture strenght were observed in inCoris Zirconia group. Highest wear voluma observed in Vita enamic group. It has been found that there are significant diffrences between all groups for wear and fracture resistance tests. Key Words: in vitro, ceramic, wear, fracture, resistance, CAD/CAM