Berksun, SemihYazgan, Yaşar Kemal2022-04-212022-04-212003http://hdl.handle.net/20.500.12575/79271The purpose of this study is based on the evaluation of aesthetic and mechanical properties of ceramic crown systems. Main goal of this study is to investigate today's popular pressable all-ceramic crown systems. In prostodontics, there is a lack of aesthetics in metal-ceramic restorations as the limiting transmission of light by the metal substructure. This caused a great interest in metal free all-ceramic restoration systems. IPS Empress 1-2, Finesse All Ceramic, Creapress and conventional metal ceramic systems as a control group were choosen for this study. Twelve pressable all-ceramic and metal-ceramic crown samples were fabricated for each group in standart dimensions by using acrylic resin index and subjected to limited aging procedure by thermal cycling. Colorometric measurements were done before and after the aging period, all crown samples were mechanically tested to determine the fracture strenghts. Considering statistical analysis, metal ceramic crown system revealed the highest fracture strength values. IPS Empress 2 and Finesse shading systems resulted the highest values respectively among the metal free all ceramic systems. IPS Empress 1, Creapress shading and Finesse layering had acceptable strengths. The lowest strength values were recorded in Creapress layering technique. It is critically important to provide more aesthetic results in metal free all ceramic systems. In this study, commonly used Vita A2 shade was selected. However it is found that, according to the colorometric measurements, the ceramic ingots and the ceramic powders produced by the mentioned products' manufacturers seemly with Vita A2 shade were not coincided with each other. It would be difficult for clinicians and patients to provide the selected shade in final restorations by using a single universal shade guide. Within the limits of this study, it can be concluded that the68 manufacturers have to present individual shade guides for their specific products and more acceptable ceramic systems regarding color characterisation. Ceramics are known to preserve their natural looking and withstand discoloration in oral environment for long time periods. In this study ceramic crown systems were subjected to limited thermal cycling and water storage to simulate oral environment. The changes in color differences raised by aging were recorded using chromameter. It is statically found that aging had no effect on ceramic color. This finding includes both metal ceramics and pressable ceramics. Key words: all-ceramic crowns, fracture strength, color, aesthetics.trDiş hekimliğidoctoralThesis