1Department of Periodontology, College of Dentistry, Chonbuk National University, Korea.
2Reseach Institute of Oral Bio-Science, Chonbuk National University, Korea.
Correspondence: Hyung-Seop Kim, Department of Periodontology, College of Dentistry, Chonbuk National University, 634-18, gumam-dong Dukjin-gu, Chonju, Korea. Tel: +82-63-250-2115, Fax: +82-63-250-2259 cbuperio@chonbuk.ac.kr