*Satoru Watanabe1, Akikazu Shinya2,3, Minori Hatta1, Yoshiki Ishida2, Daisuke Miura2, Kentaro Nakajima2, Harunori Gomi1
(1. The Nippon Dental University School of Life Dentistry at Tokyo Department of Crowns and Bridges, 2. The Nippon Dental University School of Life Dentistry at Tokyo Department of Dental Materials Science, 3. University of Turku Department of Prosthetic Dentistry and Biomaterials Science, Institute of Dentistry)