1. Department of Preventive Dentistry, Kyungpook National University School of Dentistry, Daegu, Korea.
2. Department of Preventive Dentistry & Public Oral Health, Yonsei University College of Dentistry, Seoul, Korea.
3. Department of Preventive and Public Health Dentistry, Chosun University School of Dentistry, Gwangju, Korea.
4. Department of Preventive and Public Health Dentistry, College of Dentistry, Gangneung-Wonju National University & Research Institute of Oral Science, Gangneung, Korea.