الفهرس 
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Abstract
This study evaluated the effect of aging using sodium hypochlorite as aging medium on the color stability of zirconia ceramic with different thickness and on the shear bond strength of the same ceramic which was subjected to different surface treatments.
Forty five samples were constructed from zirconia ceramic (prettau). Samples were divided into two groups according to the measuring test (15 color, 30 shear bond strength). The first for measuring color stability which was further divided into three subgroups according to the thickness of the ceramic (0.7mm, 1mm, 1.5mm) while the second group for measuring shear bond strength and further divided into three subgroups according to the type of surface treatment that was done (control, hydrofluoric acid etching, sandblasting), each subgroup was subdivided into two classes the first for measuring bond strength before aging while the second for measuring shear bond strength after aging.
Data were collected, tabulated and statistically analyzed with the following conclusions:
(1) Aging had significant effect on the color change of zirconia ceramic.
(2) Color change increased with the increase in the thickness of the ceramic disc.
(3) Hydroflouric acid etching and sandblasting as a methods of surface treatment of zirconia ceramic are not reliable methods for production of safe and strong bond with zirconia.
(4) There was no significant effect in the shear bond strength between the sandblasted zirconia and the control zirconia which was not subjected to any surface treatment before aging.
(5) Aging has significant effect on the control zirconia samples which showed decrease in the shear bond strength.
(6) There was increase in the shear bond strength of the sandblasted zirconia with aging but this increase is not significant.