1. Department of Dental Hygiene, College of Health Science, Dankook University, Cheonan, Korea
2. Research Institute, THOMASTONE Co., Ltd, Cheonan, Korea
3. Department of Public Health Science, Graduate School, Dankook University, Cheonan, Korea
4. Research Institute, Kai-i Company, DaeJeon, Korea
5. Department of Preventive Dentistry, College of Dentistry, Dankook University, Cheonan, Korea