Hao Liu1, Kai Gao2, Hong Lin3, Yu Zhang4, Binbin Li5. 1. 1 Central Laboratory, Peking University School and Hospital of Stomatology, Beijing, PR China. 2. 2 Key Laboratory of Human Diseases Comparative Medicine, Ministry of Health, Beijing, PR China; Institute of Laboratory Animal Science, Chinese Academy of Medical Sciences & Comparative Medicine Centre, Peking Union Medical College, Beijing, PR China. 3. 3 Department of Dental Materials, Peking University School and Hospital of Stomatology, Beijing, PR China. 4. 4 Department of Oral Implantology, Peking University School and Hospital of Stomatology, Beijing, PR China. 5. 5 Department of Oral Pathology, Peking University School and Hospital of Stomatology, Beijing, PR China.