Affiliation: | 1. Department of Public Health, Graduate School of Environment and Public Health Studies, Yeungnam University, Daegu, Korea;2. Department of Dental Hygiene, College of Science and Technology, Kyungpook National University, Daegu, Korea;3. Department of Preventive Medicine and Public Health, College of Medicine, Yeungnam University, Daegu, Korea;4. Department of Dentistry, College of Medicine, Yeungnam University, Daegu, Korea |