Assessment of zirconia fluorescence after treatment with immersion in liquids, glass infiltration and aging

The aim of this study was to evaluate the fluorescence of white zirconia immersed in coloring and fluorescence liquids subjected to glass infiltration and aging. Sixty zirconia discs were machined and divided into groups. Ten discs received no treated before sintering (NT group), ten discs were immersed in a coloring liquid (A2 group), and ten discs were immersed in a fluorescent liquid (F group). The other thirty discs were infiltrated by glass after the previous treatments (NT+I, A2+I, and F+I groups). The composition of the commercial liquids was characterized by X-Ray fluorescence. Diffuse reflectance and total fluorescence were evaluated before and after the aging protocol, made in autoclave for 4 hours at 134 °C. The X-Ray fluorescence analysis found a high concentration of Fe2O3 (80.7 at%) in the composition of the coloring liquid and of Bi2O3 (54.2 at%) and Cl (45.2 at%) in the fluorescence liquid. Greater reflectance was observed in the glass infiltrated groups, in particular NT+I and F+I. Fluorescence 3D maps of the groups submitted to immersion showed a higher total fluorescence than the NT group, except for the A2 group. The F group showed the highest fluorescence, being 12.8 times greater than the NT group. The fluorescence emission occurred in the region between 350 and 550 nm after an excitation between 290 and 360 nm. Regarding aging, the presence of the glass infiltrated layer protected the samples from hydrothermal degradation.
This work was supported by the Coordination for the Improvement of Higher Education Personnel, Brazil [grant number 88881.119044/2016-01] ; and the Foundation for Science and Technology, Portugal [UID/EEA/04436/2013 by FEDER funds, POCI-01-0145-FEDER-006941 NORTE 01-0145-FEDER-000018] .