Abstract
The purpose of this paper was to evaluate if a density gradient was present in green (unsintered) titanium powder samples prepared by cold isostatic pressing, and to investigate to what extent this density gradient could cause a deformation in sintered titanium dental copings (inner parts of dental crowns) due to differentiated sintering shrinkage. Three identical cylinder shaped samples were prepared at 700 MPa and the average 1 mm layer density was measured. A very small but reproducible density gradient was found (0.6 units of percentage) from the powder body surface in toward the centre. The density varied from 90.1 to 90.7%. An image analysis on sintered copings lined out the density gradient along the shape. Considering the risk of obtaining substantial deformation when preparing titanium dental copings using powder metallurgy at the pressure used, the small density gradient found was regarded as harmless.
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