1. Graduate student, Department of Dentistry, College of Medicine, The Catholic University of Korea, Seoul, Korea.
2. Private practice, Clinical Professor at Department of Orthodontics, The Catholic University of Korea; Seoul National University; and Korea University, Seoul, Korea.
3. Research Assistant Professor, Department of Dentistry, College of Medicine, The Catholic University of Korea, Seoul, Korea, and Visiting Professor, Department of Postgraduate Studies, Universidad Autonóma del Paraguay, Asunción, Paraguay.
4. Associate Professor and Chair, Postgraduate Orthodontic Program, Arizona School of Dentistry & Oral Health, AT Still University, Mesa, Ariz, and Adjunct Professor, the Graduate School of Dentistry, Kyung Hee University, Seoul, Korea.
5. Associate Professor, Department of Orthodontics, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
6. Professor, Department of Orthodontics, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.