1. Children Loving Dental Clinic, Seosan 31978, Republic of Korea
2. Department of Pediatric Dentistry, College of Dentistry, Kyung Hee University, Kyung Hee University Hospital at Gangdong, Seoul 05278, Republic of Korea
3. Department of Pediatric Dentistry, College of Dentistry, Kyung Hee University, Kyung Hee University Medical Center, Seoul 02447, Republic of Korea
4. Department of Pediatric Dentistry, Kyung Hee University Medical Center, Seoul 02447, Republic of Korea