*Yoshihiro Takeda1, Kanetaka Yamaguchi1,2, Masahiro Yamanaka1, Kouta Fujiura1, Morio Ochi1
(1. Health Sciences University of Hokkaido,Division of Fixed Prosthodontics and Oral Implantology,Department of Oral Rehabilitation., 2. Public Health Office Health & Welfare Bureau, Sapporo)