1. Department of Periodontology Peking University School and Hospital of Stomatology Beijing P.R. China
2. National Clinical Research Center for Oral Diseases Beijing P.R. China
3. National Engineering Laboratory for Digital and Material Technology of Stomatology Beijing P.R. China
4. Beijing Key Laboratory of Digital Stomatology Beijing P.R. China
5. Department of Cariology and Endodontology Peking University School and Hospital of Stomatology Beijing P.R. China