1. Department of Periodontology, School of Dentistry, Kyung Hee University, No. 1, Hoegi-dong, Dongdaemun-gu, Seoul 130-701, Republic of Korea
2. Department of Oral and Maxillofacial Pathology and Research Center for Tooth and Periodontal Regeneration (MRC), School of Dentistry, Kyung Hee University, Seoul 130-701, Republic of Korea
3. Department of Orthodontics, School of Dentistry, Kyung Hee University, No. 1, Hoegi-dong, Dongdaemun-gu, Seoul 130-701, Republic of Korea