1Department of Periodontology, College of Dentistry, Chosun University, Korea.
2Department of Preventive Dentistry, College of Dentistry, Chosun University, Korea.
3Oral Biology Research Institute, Chosun University, Korea.
Corresponding author: Byung-Ock Kim, Department of Periodontology, College of Dentistry, Chosun University, 421 Seoseok-Dong, Dong-Ku, Gwang-ju, 501-759, Korea. Tel: +82-62-220-3856, Fax: +82-62-224-4664, bobkim@chosun.ac.kr