Effects of mixing of europium oxide in resin composites on the fluorescence characteristics and mechanical properties.

Objective: The objective of this study is to disperse europium oxide (Eu₂O₃₎ in a resin composite (RC) using a planetary centrifugal mixer and assess its effects on photoluminescence and mechanical properties.

Materials and methods: A commercially available RC was mixed with Eu₂O₃ at various concentrations using a planetary centrifugal mixer. The fabricated samples were evaluated using scanning electron microscopy and a spectrofluorometer to assess their crystal structures, particle sizes, and photoluminescence properties. Vickers microhardness measurements were performed, along with a three-point bending test. Statistical analyses were performed to assess the mechanical properties.

Results: The intensity of red fluorescence increased with the increase of europium oxide concentration. The fluorescence spectra at 613 and 620 nm exhibited higher intensities under excitation at 254 nm. Eu₂O₃ was dispersed in RC regardless of the Eu₂O₃ concentration, and no aggregation was observed. Regarding the mechanical properties, there were no significant differences in the flexural strength or modulus, and the Vickers hardness gradually increased with increasing Eu₂O₃ concentration.

Conclusion: To mix Eu₂O₃ with RC, visible fluorescence emission was observed even with increasing the Eu₂O₃ concentration, and the mechanical properties of RC were unaffected. Based on our study, a 15 wt% concentration of Eu₂O₃ is the appropriate concentration, as it achieves strong fluorescence emission without compromising the mechanical properties or color tone of the RC.