[1] Hokkaido Univ, Fac Dent Med, Dept Oral Hlth Sci, Gerodontol, Sapporo 0608586, Japan
[2] Tokyo Metropolitan Inst Geriatr & Gerontol, Itabashi Ku, Tokyo 1730015, Japan
[3] Univ Ryukyus, Grad Sch Med, Dept Publ Hlth & Hyg, Nishihara 9030215, Japan
[4] Hokkaido Univ, Grad Sch Dent Med, Dept Oral Hlth Sci, Div Prevent Dent, Sapporo 0608586, Japan
[5] Niigata Univ Med & Dent Hosp, Oral Rehabil, Niigata 9518520, Japan
[6] Tokyo Dent Coll, Dept Oral Med & Hosp Dent, Ichikawa 2728513, Japan
[7] Haradoi Hosp, Dept Dent, Fukuoka 8138588, Japan
[8] Osaka Dent Univ Hosp, Dept Oral Rehabil, Osaka 5731144, Japan
[9] Kagoshima Univ, Grad Sch Med & Dent Sci, Dept Oral & Maxillofacial Prosthodont, Kagoshima 8908544, Japan
[10] Tohoku Fukushi Univ, Dept Healthcare Management, Sendai 9818522, Japan
[11] Wakakusa Tatsuma Rehabil Hosp, Dept Dent, Daito 5740012, Japan
[12] Tokyo Med & Dent Univ, Grad Sch Med & Dent Sci, Gerodontol & Oral Rehabil, Bunkyo Ku, Tokyo 1138549, Japan
[13] Fujita Hlth Univ, Sch Med, Dept Dent & Oral Maxillofacial Surg, Toyoake 4701192, Japan