الفهرس 
Introduction .Only 14 pages are availabe for public view
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Abstract
This in vitro study was performed to evaluate the effect of different bleaching protocols on two ceramic materials regarding the color and surface roughness. Two types of ceramic materials were used in the study: Zirconia reinforced lithium silicate (Celtra®Duo) and polymer infiltrated ceramic (VITA ENAMIC®).
A total of 56 discs, 28 discs of each material were prepared (thickness 1.2 mm), each group was further subdivided into 3 subgroups (7 samples in each group) according to the bleaching protocol (control, Hydrogen peroxide, carbamide peroxide, laser).
Optical profilometer was used to assess surface roughness, spectrophotometer was used to assess color change, all data were collected, tabulated, and subjected to statistical analysis.
It was found that:
- All tested ceramics (VITA ENAMIC®, Celtra®Duo) exhibited appreciable changes in color except Celtra®Duo bleached with laser exhibited a noticeable color change.
- The surface roughness (Ra) was not shown to vary significantly as affected by bleach