Synthesis of ceria-praseodymia pigments by citrate-gel method for dental restorations

The objective of this paper was to synthesize both pure and praseodymia-doped ceria by using polymeric precursor method for their use as pigments for overlaying coating of dental ceramic restorations. These pigments were characterized by thermogravimetric and differential thermal analyses, X-ray diffraction, X-ray fluorescence, scanning electron microscopy, while UV–vis spectroscopy was used to determinate the reflectance curves of both pure and praseodymia-doped ceria. The referred pigments were added to feldspathic-glass frits in order to simulated the overlaying ceramic coatings on ceramic dental restorations. It was found to be a fluorescent coating by using the synthesized pure ceria but, a coating displaying a shade comparable to those of some commercial opaque layers when using praseodymia-doped ceria pigments with the lowest praseodymia content. Colorimetric coordinate measurements were carried out and used to plot the reflectance curves in the visible range for all types of the considered overlaying coatings.