1. Department of Removable Prosthodontics; Tsurumi University School of Dental Medicine; Kanagawa Japan
2. Department of Dental Engineering; Tsurumi University School of Dental Medicine; Kanagawa Japan
3. Division of Liberal Arts; Kogakuin University; Tokyo Japan
4. Department of Materials and Applied Chemistry; College of Science and Technology, Nihon University; Tokyo Japan
5. Engineering Materials Science; Department of Advance Materials Science, Faculty of Engineering, Kagawa University; Kagawa Japan