1Department of Periodontology, College of Dentistry, Kyungpook National University, Korea.
2Megagen co., Ltd., Korea.
Correspondence: Jo-Young Suh, D.D.S. Ph.D, Department of Periodontology, college of Dentistry, Kyungpook National University, Jung-Gu, Daegu, 702-412, Korea. jysuh@knu.ac.kr