Fluorescence and Mechanical Properties of Y₂O₃:Eu³⁺ Nanophosphor-containing Adhesive Resins

Abstract

Secure removal of remnants on tooth surfaces by rotary cutting instruments after an orthodontic treatment could be guaranteed if the orthodontic adhesive used is highly visible. Fluorescent imaging is a potentially effective solution for increasing the visibility of orthodontic adhesives. In this study, Y₂O₃:Eu³⁺ nanoparticles were synthesized by a homogeneous precipitation method followed by firing at 1,000 °C. The size of most of the synthesized nanoparticles was approximately 200 nm in diameter. The photoluminescence properties of the nanoparticles were similar to that of the typical 4f-4f transition of Eu³⁺. Regardless of the concentration of the particle, the nanoparticles were almost uniformly dispersed and remained in their polymerized bodies without deteriorating the intrinsic flexural modulus of the dimethacrylate resin. Although the fluorescence of the 10 wt%-phosphor-containing resins was adequately recognizable to the naked eye, it was suggested that the preferred concentration of Y₂O₃:Eu³⁺ nanoparticles should be more than 10 wt% in terms of fluorescence intensity.