1. Department of Prosthodontics; Seoul National University School of Dentistry; Seoul Korea
2. Department of Clinical Oral Health Science; Graduate School of Clinical Dentistry; Ewha Womans University; Seoul Korea
3. Department of Prosthodontics; Seoul National University Gwanak Dental Hospital; Seoul Korea
4. Division of Orthodontics; Department of Dentistry; School of Medicine; Ewha Womans University; Seoul Korea
5. Division of Pediatric Dentistry; Department of Dentistry; School of Medicine; Ewha Womans University; Seoul Korea