الفهرس 
Introduction and literature surveyOnly 14 pages are availabe for public view
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Abstract
Co- Cr alloys are one of the most common and widely used materials in dentistry such as removable partial dentures, crowns, dentures and orthodontic devices. Sterilization and treatment by gamma radiation are the latest available methods. Magnetic resonance imaging is the newest and perhaps the most available medical imaging technology. Also heat treatment is a process in which alloy is heated to get different microstructures and desired properties which are associated with heat treatment. In our knowledge no more available research covering the effects of gamma radiation, magnetic resonance imaging, heat treatment and aging in normal saliva on Co- Cr dental alloys properties. For this reason, the aim of our research was to study the effects of magnetic resonance imaging (MRI), aging in normal saliva, gamma radiation and heat treatment on structure, hardness, roughness and electrochemical corrosion behavior of Magnum H50 dental alloy.
In this work two samples were used, commercial Magnum H50 alloy from Travagliato (BS) - Italy and prepared Magnum H50 alloy by re-melted it and casting again. These samples were prepared in convenient shape for all experimental measurements. Then the effects of gamma radiation, magnetic resonance imaging, aging and heat treatment on structure, hardness, roughness and electrochemical corrosion behavior of used samples were measured by using X-ray diffract meter, Vickers microhardness tester, surftest S.J 201.P and Voltage Lab PGZ 100 instrument . from this studying it is clear that:-
(1-) Structure of Magnum H50 dental alloy is changed after treated by gamma radiation doses (10, 20, 30 and 40 kGy) or MRI at (1 T) for 10, 20 and 30 minutes or aging in normal saliva for 1, 4 and 6 weeks or annealing for two hours at 600, 700 and 800 C by forming new crystalline phases and changing the feature of rest crystalline phases.
(2-) Values of Vickers hardness, surface roughness parameters, electrochemical corrosion of Magnum H50 alloy after treated by gamma radiation doses (10, 20, 30 and 40 kGy) or MRI at (1 T) for 10, 20 and 30 minutes or aging in normal saliva for 1, 4 and 6 weeks or annealing for two hours at 600, 700 and 800 C are varied.
(3-) Candida Spp is stuck on Magnum H50 alloy surface after aging in normal saliva for 1, 4 and 6 weeks and the growth of Candida Spp is increased with increasing aging time. The maximum growth of Candida Spp on Magnum H50 alloy surface at 4 weeks.