1. Second Clinical Division, Peking University School and Hospital of Stomatology, Beijing 100101, China
2. National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing 100081, China
3. Center of Digital Dentistry, Peking University School and Hospital of Stomatology, Beijing 100081, China
4. Department of Chemistry, Renmin University of China, Beijing 100872, China