الفهرس 
Manufacturing Techniques of TitaniumOnly 14 pages are availabe for public view
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Abstract
Marginal accuracy of titanium framework using different manufacturing techniques in fixed partial prostheses Background Advances in additive manufacturing technology (3D Printing) and computer-aided design/computer-assisted manufacturing (CAD/ CAM) technology purportedly enhance the marginal fit of dental restorations. However, little information is available on the marginal accuracy of titanium restorations manufactured with additive and subtractive techniques. Purpose The purpose of this study was to evaluate marginal accuracy of titanium framework using different manufacturing techniques in fixed partial prostheses (Conventional casting, subtractive and additive manufacturing). Material and methods Thirty epoxy master dies duplicated from a two-abutment stainless-steel dies with an occluso-gingival height of 7.5 mm, a taper of 6° and 1 mm shoulder finish line all around using optical scanning and 3d printing technology. The design of the titanium framework was done using 3Shape software (CAD) that resembles three unit bridge to acquire Standard Tessellation Language (STL) file of the final design. Thirty titanium frameworks were fabricated and divided in to three groups according to manufacturing technique. group C (n=10): Casting manufacturing technique. group S (n=10): Subtractive manufacturing technique. group A (n=10): Additive manufacturing technique. In group (C), the framework wax pattern was fabricated using 3D printed wax pattern then invested in the mold. Commercially pure (CP) Ti was cast using titanium casting machine. In group (S), The STL file of the final design of titanium framework was send to a computer aided manufacturing (CAM) machine. In group (A) The STL file of the final design of titanium framework was send to a metal rapid prototyping (3D printing) machine. Each framework was luted to epoxy die under 2 kg static load. The luted assembly was cut longitudinally at center of the casting. The clearance between die and framework was measured at different measurement locations along cervical shoulder and data (mm) for exterior or interior shoulders (n =30 bridges; 60 shoulders) were averaged in terms of vertical gap (VG) and horizontal discrepancy (HD), then were statistically analyzed by ANOVA/Tukey test (P < 0.05). Results The VG and HD values of titanium framework fabricated by subtractive technology showed high marginal accuracy compared to the others at all measurement locations of exterior and interior shoulders. However, there was no statistical difference (P > 0.05) among the subtractive and additive technology. Casting titanium showed the least marginal accuracy in both VG and HD values. Conclusion The measured marginal accuracies of titanium framework fabricated by the subtractive and additive techniques demonstrated clinically acceptable marginal discrepancies on the working dies.