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 People's Republic of China
2. Department of Emergency; Peking University School and Hospital of Stomatology, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing Key Laboratory of Digital Stomatology; Beijing People's Republic of China
3. Department of Restorative Dentistry; University of Washington; Seattle Washington, USA