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

This study evaluated 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 treatment before sintering (Group NT), ten discs were immersed in a coloring liquid (Group A2), and ten discs were immersed in a fluorescent liquid (Group F). The other thirty discs were infiltrated with glass after the previous treatments (Groups NT + I, A2+I, and F + I). The composition of the liquids was characterized by X-Ray fluorescence. Additional superficial roughness and X-Ray diffraction measurements were made. Diffuse reflectance and total fluorescence were evaluated before and after aging, performed in an autoclave at 134 °C for 4 h. By X-Ray fluorescence analysis, a high concentration of Fe₂O₃ (80.7 at%) was found in the composition of the coloring liquid; Bi₂O₃ (54.2 at%) and Cl (45.2 at%) were found in the fluorescence liquid. Greater reflectance was observed in the glass infiltrated groups, in particular Groups NT + I and F + I. Mean values found for arithmetic average roughness (Ra) varied around 0.2 μm. The 3D Fluorescence maps of the groups submitted to immersion showed a higher total fluorescence value than Group NT, except for Group A2. Group F showed the highest fluorescence value that was 12.8 times higher than the value of Group NT. Fluorescence emission occurred in the region between 350 and 550 nm after excitation ranging between 290 and 360 nm. The presence of the glass infiltrated layer protected the samples from hydrothermal degradation.