Affiliation: | 1. Department of Dental Hygiene, Dong‐Eui University, , Busan, Korea;2. Department of Dental Laboratory Science and Engineering, College of Health Science, Korea University, , Seoul, Korea;3. Department of Dental Ecology, School of Dentistry, University of North Carolina, , Chapel Hill, NC, USA;4. Department of Preventive Medicine, Inje University, , Busan, Korea;5. Department of Preventive and Public Health Dentistry, School of Dentistry, Seoul National University, , Seoul, Korea;6. Department of Dental Hygiene, Jin‐Ju University, , Jinju, Korea |