Dr. Kee-Joon Lee is a professor of the Department of Orthodontics, Yonsei University College of Dentistry, Seoul, Korea. He received specialty training and PhD degree from the College of Dentistry, Yonsei University. He was a visiting scholar at University of Pennsylvania School of Dental Medicine in 2002-2004 and at the Division of Plastic Surgery, the Children’s Hospital of Philadelphia in 2010-2011. He has served as an adjunct professor at the Department of Orthodontics, University of Pennsylvania and Temple University. He is the first who demonstrated the miniscrew-assisted rapid palatal expander (MARPE) for adults in AJO-DO. His fields in research include clinical biomechanics regarding TADs application and the suture biology for craniofacial orthopedics.