Thesis (M.Sc.) - Cairo University - Faculty of Oral and Dental Medicine - Department of rosthodontics

The aim of this in-vitro study was to assess the effect of the surface finish protocol of pressed zirconia reinforced lithium silicate ceramics on the surface roughness & color stability under different pH oral media. Methodology: thirty surfaces (n=30) of pressed zirconia reinforced lithium silicate samples were tested, samples were fabricated and divided into two main groups (n=15) according to surface finish protocol; glazed group and polished group. Then, The samples of each group were further subdivided into three subgroups according to the media tested (n=5): Artificial saliva, coffee, carbonated orange juice. A cylinder of 10 mm diameter and 6.5 mm thickness was designed using Exocad software. five cylinders were milled from Cad wax blank, then the cylinders were invested for wax burnout procedure. afterwards, pressing of zirconia reinforced lithium silicate ingots were made. Each ceramic cylinder was cut into three discs with 1.5 mm thickness using isomet 4000. All the discs were finished with fine grit diamond stone on both sides according to manufacturer instructions, a marginal notch with a diamond stone was made on the side that will receive polishing to be able to differentiate between the polished and the glazed sides. Then, discs were glazed on one side and polished on the other side resulting in 15 glazed and 15 polished surfaces

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