1. Department of Dentistry, Inha International Medical Center, Incheon, Korea.
2. Department of Periodontics, Asan Medical Center & Department of Dentistry, University of Ulsan College of Medicine, Seoul, Korea.
3. Department of Periodontology, College of Dentistry and Institute of Oral Bioscience, Chonbuk National University, Jeonju, Korea.
4. Research Institute of Clinical Medicine of Chonbuk National University-Biomedical Research Institute of Chonbuk National University Hospital, Jeonju, Korea.