1. Faculty of Dental Medicine, Hokkaido University, Sapporo 060-8586, Japan
2. Department of Materials Science and Engineering, Kitami Institute of Technology, Kitami 080-8507, Japan
3. Faculty of Dentistry, Mahidol University, Bangkok 10400, Thailand
4. School of Health Science, Kyushu University of Health and Welfare, Nobeoka 882-8508, Japan
5. Graduate School of Biomedical Sciences, Nagasaki University, Sakamoto 1-7-1, Nagasaki 852-8102, Japan
6. Department of Applied Chemistry and Bioscience, Chitose Institute of Science and Technology, Chitose 066-8655, Japan