1. Department of Periodontology and Dental Research Institute, Seoul National University School of Dentistry, Seoul, Korea.
2. Program of Clinical Dental Education and Dental Research Institute, Seoul National University School of Dentistry, Seoul, Korea.
3. Plasma Technology Research Center, National Fusion Research Institute, Gunsan, Korea.
4. Department of Energy Systems (Nuclear) Engineering, Seoul National University School of Engineering, Seoul, Korea.