Nano Biomedicine

Introduction of Rare-Earth-Element-Containing ZnO Nanoparticles into Orthodontic Adhesives

Shuichi YAMAGATA1, Yusuke HAMBA1, Ko NAKANISHI1, Shigeaki ABE2, Tsukasa AKASAKA2, Natsumi USHIJIMA3, Motohiro UO4, Junichiro IIDA1, and Fumio WATARI2

1Department of Orthodontics, Graduate School of Dental Medicine,
2Department of Biomedical Materials and Engineering, Graduate School of Dental Medicine,
3Support Section for Education and Research, Graduate School of Dental Medicine,
Hokkaido University, Sapporo, Japan.
4Advanced Biomaterials, Department of Restorative Sciences,
Graduate School of Medical and Dental Sciences,
Tokyo Medical and Dental University, Tokyo, Japan.

Nano Biomedicine 2012;4(1):11-17, (Jun 30)

To make orthodontic adhesives visible as needed is valuable for safer and complete removal of them after orthodontic treatments. An attempt was made on doping trivalent europium ions into lattices of zinc oxides to make orthodontic adhesives visible by irradiation with purple or near ultraviolet light. The primary crystals of the synthesized products exhibited various sizes. However, overall, their diameters were on the nanoscale. The XRD patterns of them were in good agreement with those of hexagonal ZnO. However, the patterns also indicated the existence of another crystal-line substance that could be indexed as Eu2O3. These results lead to the conclusion that ZnO:Eu3+ nanoparticles were suitably synthesized via a homogeneous precipitation method. As for the polymer adhesives containing the ZnO:Eu3+ nanoparticles, the photoluminescent spectra exhibited characteristic excitation and emission peaks corresponding to the intrinsic intra-4f transitions of Eu3+. In addition, the yielding loads of the composite specimens did not deteriorate, regardless of the concentration of the ZnO:Eu3+ nanoparticles within the proportion of 1-3 wt%. The results obtained in this study suggest that the introduction of Eu3+-doped ZnO nanoparticles into orthodontic adhesives is feasible.

Key words: fluorescence, photoluminescence, europium, zinc oxide, orthodontic adhesive

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