Kwangchul Choy, DDS, MS, PhD, is a former professor of orthodontics at Yonsei University. He completed his orthodontic training at Yonsei University and was a research fellow and visiting professor at the University of Connecticut. Dr Choy is currently a clinical professor at Yonsei University as well as an adjunct professor of orthodontics at Ewha Womans University. He has published over 30 papers and book chapters in the field of biomechanics of tooth movement and orthodontic appliances. Dr Choy lectures around the world on biomechanics and maintains a private practice in Seoul, South Korea.