[1] Asahi Univ, Sch Dent, Dept Community Oral Hlth, Mizuho Ku, 1851 Hozumi, Gifu 5010296, Japan
[2] Columbia Univ, Med Ctr, Dept Microbiol & Immunol, 701 West 168th St, New York, NY 10032 USA
[3] Meikai Univ, Sch Dent, Dept Oral Hlth & Prevent Dent, Sakado, Saitama 3500283, Japan
[4] Asahi Univ Hosp, Mizuho Ku, 3-23 Hashimoto Cho, Gifu 5008523, Japan