1. Department of Preventive Dentistry, School of Dentistry, Kyungpook National University, Daegu, Korea.
2. Department of Psychiatry, Institute of Behavioral Science in Medicine, Yonsei University College of Medicine, Seoul, Korea.
3. Department of Sociology, Younsei University College of Social Science, Seoul, Korea.
4. Department of Preventive Medicine, Yonsei University College of Medicine, Seoul, Korea.
5. Department of Dental Hygiene, Ulsan College, Ulsan, Korea.
6. Dental Hygiene, Daegu Health College, Daegu, Korea.