الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
This study was intended to evaluate the physico-mechanical properties of a recent nano-ceramic hybrid CAD/CAM material (Nano-ceramic hybrid material) comparing it to a nano-ceramic CAD/CAM material (Resin nano-ceramic material) regarding: flexural strength, surface micro-hardness, wear, surface roughness and bacterial adhesion. Materials and methods : A total of 80 specimens have been prepared 40 specimens for each material used (a nano-ceramic hybrid material and a resin nano-ceramic material). Specimens have been prepared with measures regarding the test parameters used. For flexural strength testing, bar shaped specimens with dimensions of 14 x 4 x 2 mm were sectioned and polished according to manufacturer instructions. The specimens were loaded in a universal testing machine and flexural strength was evaluated using a three point bending test. For surface hardness assessment, specimens with 2 mm thickness were prepared, polished and mounted in Vickers micro-hardness tester. A diamond indenter was used to produce 3 indentations in each specimen, and then VHN was calculated for each material. For wear measurement, specimens with dimensions of 10 x 7 x 6 mm, were mounted in pin on ring tribometer and the amount of weight loss after testing was determined as an indicator of wear. A stylus profilometer was used to evaluate the surface roughness of disc shaped specimens, sectioned from each material with dimensions of 8 x 2 mm, in three directions. For the bacterial adhesion test, the same specimens from the roughness test were used to evaluate the adhesion of S.mutans to the surface of each material after incubation at for 24 hours. The correlation between surface roughness and bacterial adhesion was also investigated. Results : The nano-ceramic hybrid CAD/CAM material exhibited significantly higher flexural strength and surface hardness than the nano-ceramic CAD/CAM material. It also showed significantly lower surface roughness and surface bacterial adhesion and lower wear that were not significantly different. Conclusion : The Nano-ceramic hybrid CAD/CAM material showed better physico-mechanical properties compared to the nano-ceramic CAD/CAM material. Recommendations: Further clinical studies are recommended on similar materials to assess the best CAD/CAM resin composite qualified materials for dental restorations.