1. Department of Biochemistry , School of Dentistry, , Daegu 41940 , Korea
2. Kyungpook National University , School of Dentistry, , Daegu 41940 , Korea
3. Department of Oral Physiology, School of Dentistry, Pusan National University , Yangsan 50612 , Korea
4. Department of Oral Pathology, School of Dentistry, Pusan National University , Yangsan 50612 , Korea
5. Department of Periodontology , School of Dentistry, , Daegu 41940 , Korea