Rare earth oxide-containing fluorescent glass filler for composite resin

In recent dental care, esthetic restorative materials such as composite resin and porcelain have been widely used and studied. However, their good esthetics makes the visual inspection of restored teeth difficult. In this study, a fluorescent glass filler containing rare earth oxides - which are well-known fluorescent materials - was prepared and used in composite resin to enhance visual inspection capability with small change in color. For example, when irradiated with near ultraviolet light, an Eu2O3-containing filler fluoresced clearly and visibly. The fluorescence intensity of the prepared composite resin increased with increase of Eu2O3 content in the glass filler and with filler/resin ratio in the resin. Despite the clear fluorescence, the effect of Eu2O3 on the color change of composite resin was quite small - even when up to 10 wt% Eu2O3 was added to the glass filler. Tb4O(7-) and Dy2O3-added fillers also showed clear fluorescence, just like Eu2O3-added filler. Therefore, fluorescent glass fillers for composite resins, resulting in small color change in the latter, were successfully prepared in this study.