الفهرس 
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Abstract
Abstract
Purpose: This study evaluates the mechanical properties of different implant abutments materials and comparing their stress analysis distribution in the cortical bone. Materials and methods : The three abutment materials (Bio HPP, Nano -fiber Reinforced Composite and Glass Fiber Reinforced Composite) in this study were studied in three tests. The first test was applied on Fifteen bar specimens divided into three groups. The second test of the specimens was applied on Fifteen two- parts abutments (the first part was custom-made fabricated from the three tested materials resemble prepared tooth crown cemented to the second Ti-base part). The third test was Finite Stress Analysis of the abutment materials on the surrounding structures. The first test of the study was Fifteen Bar-shaped specimens of the three abutment materials had (25mm length, 4mm thick and 5mm width), fabricated and divided into three groups, 5 bar for each. group I: High Performance Polymer Hybrid abutments (Bio-HPP). group II: The Experimental Nanofibers material will be fabricated by Electrospinning technique of TEOS and PVA solutions by spinning apparatuses and Finally, mixed to the fabricated composite. The Bar specimens subjected to flexural stress and deflection tests using universal testing machine. The second test of the study was fifteen abutments divided into 5 for each. Group. I: CAD/CAM fabricated Bio-HPP abutment part. group II: Nanofiber reinforced composite custom made abutment. group III: Glass fiber reinforced composite custom made abutments. These abutments parts were cemented to the Ti-base and optically scanned in order to fabricate all ceramic crown for premolar, using (CAD/CAM) system. The crowns will be cemented on the abutments with temporary luting cement . The samples were individually mounted on a computer controlled materials testing machine (Model 3345; Instron Industrial Products, Norwood, MA, USA) with a load cell to test the fracture resistance and the data were recorded using computer software (Instron® Bluehill Lite Software). The stress analysis test of the three materials in the surrounding structure. The ―Premolar ceramic crown restoration‖, had a three dimensional scanner was utilized for its modeling, (Roland Active Piezoelectric Sensor and computer that was exported to Finite Element Analysis program. Results: Deflection test mean and slandered deviation of bar specimens in the three groups showed significant difference where gp I, II, III were 3.052±0.040, 0.984±0.106, 2.028±0.027
N. receptively. Comparisons between the fracture resistance means and slandered deviation of the tested three groups. 642.00±.5.637, 306.00±30.496 and 514.40±12.915 respectively. There is a significant difference also between them. Finite Element Stress Analysis of applied vertical load on the three abutment materials reveal that there was no clear difference but the least stresses created on bone with Nano glass fiber composite abutment(16.2Mpa) followed with glass fiber reinforced composite (17.32) then BioHPP abutment (18.55Mpa). Conclusion: Within the limitations of this study, promising fracture strengths and fracture types were found for BioHPP abutments with titanium base restored with monolithic lithium disilicate crowns had the highest fracture resistance The abutments had the potential to withstand maximum occlusal forces, and also showed better fracture patterns than the FRC and NFRC abutments. a higher elastic modulus of the ceramic crowns associated with lower elastic modulus of the hybrid abutment shows a better stress distribution on the set, suggesting a promising mechanical behavior
Key Words: implant abutment, Bio HPP, Nanofiber, Fiber reinforced Composite Finite Element Stress Analysis