الفهرس 
AcknowledgementOnly 14 pages are availabe for public view
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Abstract
Statement of problem; Ceramics are the most esthetic appealing material used in fixed prosthodontics. Oral media pH is unstable due to consumption of different beverages; these beverages can be acidic, by which they may adversely affect the material of the prosthesis either by staining it or by affecting its surface roughness depending on the material it was made of.
Aim of study; The aim of this study was to assess color stability and surface roughness change of Lithium disilicate and Hybrid ceramics after immersion in staining acidic solutions with different pH values (carbonated orange and coffee beverages).
Materials and methods; 26 plates of each material were sectioned using Isomet 4000, Then the samples were randomly divided into 2 subgroups (n=13), After plates preparation baseline readings of color parameters were done using spectrophotometer, for the roughness using stylus profilometer, surface topography was assessed by scanning with Scanning Electron Microscope (SEM). Then each subgroup of material was immersed in an acidic beverage (Coffee and Miranda orange) for 168 hours/7 days then retested for the previously mentioned parameters. Differences between pre and post immersion readings of color parameters and surface roughness for the tested groups and subgroups were calculated, tabulated and statistically analyzed.
Results; For the color change; it was found that regardless to treatment solution, Enamic group recorded statistically significant higher change mean value than E.max group. And regardless type of ceramic, coffee treated subgroup recorded statistically significant higher change mean value than orange treated subgroup, While in Enamic group; it was found that coffee treated subgroup recorded statistically non-significant higher change mean value than orange treated subgroup. And in E.max group; it was found that orange treated subgroup recorded statistically non-significant higher change mean value than coffee treated subgroup. For the roughness; it was found that regardless to treatment solution, Enamic group recorded statistically significant higher change mean value with % change than E.max group. And regardless to ceramic group, coffee treated subgroup recorded statistically significant higher change mean value with % change than orange treated subgroup. While in Enamic group; it was found that coffee treated subgroup recorded statistically non-significant higher percentage change and mean value than orange treated subgroup. And in E.max group; it was found that coffee treated subgroup recorded statistically non-significant higher change mean value than orange treated subgroup.
Conclusions; Within the limitations of this study, it can be concluded that Coffee has stronger staining potency and erosive effect on tested ceramic materials than carbonated orange, and when exposed to acidic beverages, Vita Enamic is more susceptible to color and roughness change than E.max CAD.