1. Department of Periodontics, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041, China
2. College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, Sichuan 610065, P. R. China
3. Laboratory of Clinical Nuclear Medicine, Department of Nuclear Medicine, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, 610065, P. R. China