الفهرس 
Introduction and literature surveyOnly 14 pages are availabe for public view
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Abstract
Porcelain and zirconia are widely used in dental restoration such as replacement, dental filling. Sterilization and treatment by gamma radiation are the latest available methods. Magnetic resonance is the newest and perhaps the most available medical imaging technology. In our knowledge no more available research covering the effects of gamma radiation, magnetic resonance imaging and aging (stored) in normal saliva on structure and mechanical properties of dental ceramic restorations. For this reason, the aim of this research was to investigate the effects of gamma radiation, magnetic resonance (MRI) and aging (stored) in normal saliva on structure, hardness, roughness and adhesion Candida Spp(dense andarea) of dental ceramic restoration. To verify these aims:-Two ceramic materials were used, porcelain specimens (Vita VMK, master, VITA Zahnfabrik, Germany) and Zirconium blank for dental restorations, class II ceramic from white peaks Dental Systems GmbH & Co. KG, langeheide 9 D-45239 Essen. These samples were prepared in convenient shape for all experimental measurements. The structure, hardness, surface roughness and adhesion Candida Spp (dense andarea) of used samples were measured using Shimadzu X–ray diffractometer (Dx–30, Japan), Vickers microhardness tester (Model FM.7 Future-Tech. Corp. Tokyo Japan), surftest S.J 201.P and Voltage Lab PGZ 100 instrument and optical microscope. from this studying it is clear that:-Structure of porcelain and zirconia as dental ceramic restoration changed after exposure to gamma radiation doses (10, 20 and 30 kGy) or (10, 20 and 30 Gy) or MRI (at 1.5 T for 15 and 30 minutes) or aging (stored) in normal saliva for 1, 2 and 3 months such as amorphous base line, amorphous area and formed crystalline phases. Vickers hardness and surface roughness parameters of porcelain and zirconia dental materials changed after exposure to gamma radiation, MRI and aging (stored) in normal saliva. Adhesion Candida Spp(dense andadhesion area) of porcelain and zirconia dental materials changed after aging in normal saliva.