1. Department of Oral Health, Graduate School of Health and Welfare, Dankook University, Cheonan, Korea
2. Division of Infectious Diseases, Department of Internal Medicine, Dankook University Hospital, Dankook University College of Medicine, Cheonan, Korea
3. Department of Dental Hygiene, College of Health Science, Dankook University, Cheonan, Korea
4. Department of Preventive Dentistry, College of Dentistry, Dankook University, Cheonan, Korea