1. The State Key Laboratory Breeding Base of Basic Science of Stomatology & Key Laboratory of Oral Biomedicine Ministry School and Hospital of Stomatology Wuhan University, TaiKang Center for Life and Medical Sciences Wuhan University Wuhan 430072 P. R. China
2. Department of Periodontology University of Bern 3010 Bern Switzerland
3. Medical Research Institute School of Medicine Wuhan University Wuhan 430071 P. R. China