2017 Volume 9 Issue 1 Pages 15-22
Subsequent to the orthodontic treatment, removal of residual colorless adhesives from tooth surfaces by cutting instruments with the lowest possible iatrogenic damage has been a long-standing challenge. Fluorescent imaging can be one of the most effective solutions. Y2O3:Eu3+ particles were synthesized by a homogeneous precipitation method and the subsequent calcination was performed at various temperatures. The particles had a narrow size distribution (200-300 nm) and showed sharp crystallinity independent of the calcination temperatures above 800 °C. In this study, 1,000 °C is confirmed to be the optimum calcination temperature. Although the reason for the decline in emission intensity of the 1,100 °C-calcined particles is still unclear, loss of spherical shape associated with excessive crystal grain growth and simultaneous sintering to each other by firing is a possible explanation. The emission from the phosphor-containing resins, intended for use in orthodontic adhesives, is appreciable although the emission intensity of the resins was weak even if their content was 20 wt.%. The decrease in emission intensity may be attributed to the scattering by the particles or cross relaxation processes. We conclude that the crystalline Y2O3:Eu3+ particles calcined at 1,000 °C could be applicable for further development of photoluminescent orthodontic adhesives.