1. Department of Periodontology, Research Institute for Oral Science, Gangneung-Wonju National University College of Dentistry, Gangneung, Korea.
2. Department of Microbiology and Immunology, Research Institute for Oral Science, Gangneung-Wonju National University College of Dentistry, Gangneung, Korea.
3. Department of Periodontics, Kangbuk Samsung Hospital, Seoul, Korea.