1. Department of Periodontology and Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Korea.
2. Deartment of Dentistry, Catholic Kwandong University, International St. Mary's hospital, Incheon, Korea.
3. Department of Dental Science and Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Korea.
4. Plasma Technology Research Center, National Fusion Research Institute, Gunsan, Korea.
5. Department of Energy Systems (Nuclear) Engineering, Seoul National University School of Engineering, Seoul, Korea.