1. Private Practice; Department of Orthodontics, The Catholic University of Korea and Seoul National University, Seoul, Korea.
2. Dental Department, Iraqi Armed Hospital, Ministry of Defense, Bagdad, Iraq.
3. Department of Postgraduate Studies, the Universidad Autonóma del Paraguay, Asunción, Paraguay.
4. Postgraduate Orthodontic Program, Arizona School of Dentistry & Oral Health, A.T. Still University, Mesa, AZ, USA.
5. Graduate School of Dentistry, Kyung Hee University, Seoul, Korea.
6. Department of Orthodontics, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
7. Department of Oral Anatomy, Dental Research Institute and School of Dentistry, Seoul National University, Seoul, Korea.
8. Division of Orthodontics, Department of Dentistry, St. Vincent's Hospital, College of Medicine, The Catholic University of Korea, Suwon, Korea.