American Board of Orthodontics (ABO) Emeritus Professor, Department of Orthodontic. The Catholic University of Korea Former Dean, graduate school of clinical dental science, The Catholic University of Korea Former President, Korean Association of Orthodontists Invited speaker: 1. 2024 New Orleans AAO: Efficient application of TADs and 3D technology in Class II non-extraction treatment 2. 2023 Chicago AAO: New Strategies to Break the Limitations of Non-extraction Treatment 3. 2020 Yokohama, IOC: Efficient Non-Extraction Approach to Correct Class II Malocclusion 4. 2019 Los Angeles, AAO: TAD anchorage for class II correction. 5. 2018 Washington, DC AAO: A simple non-extraction approach to correct Class II malocclusion 6. 2017 San Diego AAO: New Approaches in Class II Correction with a Simple and Innovative Method 7. 2015 San Francisco AAO: Corticotomy-assisted accelerated space closure of a missing molar by utilizing the 3rd molar