**5. Conclusions**

The surface modification technique using EPD and BG for orthodontic stainless steel offers the possibility of developing new orthodontic metallic appliances with satisfactory esthetic appearance and remineralization ability, without being cytotoxic.

**Acknowledgments:** The authors thank Masataka Fukuchi at Yokohama City Industrial Technical Support Center for his expert technical assistance with the progressive load scratch test. The authors also thank Kazuki Sobue and Takashi Murakami at Shimadzu Corporation for lending their expertise on the application of color measurement. This study was partially supported by a Grant-in-Aid Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology, Japan (No. 25463195).

**Author Contributions:** Masahiro Iijima conceived and designed the experiments; Kyotaro Kawaguchi and Masahiro Iijima performed the experiments; Masahiro Iijima, Kazuhiko Endo, and Itaru Mizoguchi wrote the paper.

**Conflicts of Interest:** The authors declare no conflict of interest.
