1Department of Periodontology, Graduate School of Clinical Dentistry, Ewha Womans University, Korea.
2Department of Periodontics, Ewha Medical center, Mokdong Hospital, Ewha Womans University, Korea.
Corresponding author: Seoung-Ho Lee, Department of Periodontology, Graduate School of Clinical Dentistry, Ewha Womans University, 911-1 MokDong, YangCheon-Ku, Seoul, Korea. Perio772@ewha.ac.kr