1. Institute for Medical and Dental Engineering, Tokyo Medical and Dental University, 2-3-10 Kanda-Surugadai, Chiyodaku, Tokyo. Japan
2. Department of Chemistry, Tsurumi University, 2-1-3 Tsurumi, Tsurumiku, Yokohama, Japan
3. Department of Prosthodontics, School of Dentistry, Hokkaido University, North 13, West 7, Sapporo, Japan