1. Biomedical Engineering Department, Peking University, Beijing 100191, P. R. China
2. College of Future Technology, Peking University, Beijing 100091, P. R. China
3. Institute of Medical Technology, Peking University Health Science Center, Beijing 100191, P. R. China
4. National Center of Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Peking University School and Hospital of Stomatology, Beijing 100191, P. R. China