Author information:
(1)Department of Preventive Dentistry, Okayama University Graduate School of 
Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, 
Okayama 700-8558, Japan. de421015@s.okayama-u.ac.jp.
(2)Department of Community Oral Health, Asahi University of Dentistry, 1851-1 
Hozumi, Mizuho, Gifu 501-0296, Japan. tomofu@dent.asahi-u.ac.jp.
(3)Department of Preventive Dentistry, Okayama University Graduate School of 
Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, 
Okayama 700-8558, Japan. de17046@s.okadai.jp.
(4)Department of Preventive Dentistry, Okayama University Graduate School of 
Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, 
Okayama 700-8558, Japan. de17057@s.okadai.jp.
(5)Department of Preventive Dentistry, Okayama University Graduate School of 
Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, 
Okayama 700-8558, Japan. dekuni7@md.okayama-u.ac.jp.
(6)Department of Preventive Dentistry, Okayama University Graduate School of 
Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, 
Okayama 700-8558, Japan. tetsuji@md.okayama-u.ac.jp.
(7)Center of Innovative Clinical Medicine, Okayama University Hospital, Okayama 
700-8558, Japan. t-maru@md.okayama-u.ac.jp.
(8)Department of Community Oral Health, Asahi University of Dentistry, 1851-1 
Hozumi, Mizuho, Gifu 501-0296, Japan. akikohi@dent.asahi-u.ac.jp.
(9)Department of Preventive Dentistry, Okayama University Graduate School of 
Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, 
Okayama 700-8558, Japan. mmorita@md.okayama-u.ac.jp.