1. Department of Oral Implantology, Guanghua School of Stomatology, Hospital of Stomatology, Sun Yat-sen University, Guangzhou, China
2. Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
3. Department of Periodontology, Peking University School and Hospital of Stomatology, Beijing, China
4. The Second Dental Center, Peking University School and Hospital of Stomatology, Beijing, China