[1] Tokyo Metropolitan Inst Gerontol, Tokyo, Japan
[2] Mohammed V Univ Rabat, Fac Med Dent, Dept Periodontol, Lab Oral Biol & Biotechnol, Rabat, Morocco
[3] Kyushu Dent Univ, Div Community Oral Hlth Dev, Kitakyushu, Fukuoka, Japan
[4] Matsumoto Dent Univ, Dept Oral Microbiol, Shiojiri, Japan
[5] Meirin Coll, Niigata, Japan