*Toshikazu miura1, Yasuhiko kawai2, Masayasu Ito2, Asako Suzuki2, Koga Manaka2, Shizuka Tarukawa1
(1. Removable Prosthodontics, Nihon University Graduate School of Dentistry at Matsudo, 2. Department of Removable Prosthodontics and Geriatric Oral Health, Nihon University School of Dentistry of Matsudo)