1. Department of Community of Oral Health, Nihon University School of Dentistry at Matsudo, Matsudo, Chiba 271-8587, Japan
2. Department of Biochemistry and Molecular Biology, Nihon University School of Dentistry at Matsudo, Matsudo, Chiba 271-8587, Japan
3. Dentistry and Oral Surgery, Nadogaya Hospital, Kashiwa, Chiba 277-0084, Japan
4. Chiba Prefecture Government Health & Welfare Department Health Promotion Support Division, Oral Health Support Center, Chiba, Chiba 260-8667, Japan
5. Nihon University Graduate School of Dentistry at Matsudo, Community Oral Health, Matsudo, Chiba 271-8587, Japan
6. Nihon University Graduate School of Dentistry at Matsudo, Public and Preventive Dentistry, Matsudo, Chiba 271-8587, Japan
7. Department of Dental Health Policy Science, Tokyo Dental College, Chiyoda, Tokyo 101-0061, Japan