Yoon-Ah Kook1, Jae Hyun Park2, Mohamed Bayome3. 1. Department of Orthodontics, Seoul St. Mary's Hospital, Catholic University of Korea, 222 Banpo-daero, Seocho-gu, Seoul, Korea 137-701. kook190036@yahoo.com. 2. Postgraduate Orthodontic Program, Arizona School of Dentistry and Oral Health, A.T. Still University, Mesa, AZ; and Graduate School of Dentistry, Kyung Hee University, Seoul, Korea. 3. Graduate School, Catholic University of Korea; and Department of Postgraduate Studies, Universidad Autonoma del Paraguay, Asuncion, Paraguay.