1 Department of Periodontology, Peking University School and Hospital of Stomatology, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing Key Laboratory of Digital Stomatology, Beijing 100081, China.
2 The Fourth Outpatient Dental Clinic, Peking University School and Hospital of Stomatology, National Engineering Laboratory for Digtal and Material Technology of Stomatology, Beijing Key Laboratory of Digital Stomootology, Beijing 100034, China.