Evaluation of optical properties, morphological changes & surface degradability of ceramics immersed in different oral medias / Hagar Hassan khaled Gibreel ; Supervised Jylan Fouad Elguindy , Maha Ahmed Taymour

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

This study was designed to investigate the effect of different oral media on the color change, surface roughness and chemical structure of Emax Ceram and Lava Ultimate. A specially designed copper mould was used to construct standardized disc shaped ceramic samples of 10 mm diameter and 2 mm thickness. CAD-CAM was used to construct the discs of the Lava Ultimate. Thirty samples were constructed 15 sample from Emax Ceram and 15 from Lava Ultimate, each group was subdivided to 4 subgroups. Subgroup A: control group Subgroup B: 4% acetic acid Subgroup C: artificial saliva Subgroup D: alkaline water. Color change was measured for all samples in each group using spectrophotometer. Surface roughness was also measured for each group by using stereomicroscope. Computerized chemical composition analysis was done for each group using energy dispersive x-ray (EDX) unit attached to the SEM. According to the gathered results it was found that: {uF0B7}Before the immersion the (control group) (Lava Ultimate) specimens had higher surface roughness than feldspathic porcelain (Emax-Ceram). {uF0B7}After the immersion it was found that Emax-Ceram group recorded statistically significant (p < 0.05) higher color change ({u2206}E) mean value than Lava Ultimate ceramic group. But the (Lava Ultimate) specimens also had the higher roughness than (Emax-Ceram). {uF0B7}The two types of ceramics corroded in the three media. {uF0B7}Irrespective of ceramic type, it was found that 4% acetic acid group recorded the highest color change ({u2206}E) mean values followed by alkaline water group while artificial saliva group recorded the lowest color change ({u2206}E) mean value

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