1. State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University , Chengdu, Sichuan 610041, P.R. China
2. National Engineering Research Center for Biomaterials, College of Biomedical Engineering, Sichuan University , Chengdu, Sichuan 610065, P.R. China