1Department of Conservative Dentistry, College of Dentistry, Yonsei University, Seoul, Korea.
2Department of Oral Pathology, College of Dentistry, Yonsei University, Seoul, Korea.
3Department of Periodontology, College of Dentistry, Yonsei University, Seoul, Korea.
4Department of Biotechnology, College of Life Science and Biothchnology, Yonsei University, Seoul, Korea. JFIF d d Ducky d qhttp://ns.adobe.com/xap/1.0/