1. State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China.
2. Department of Periodontology, Institute and Hospital of Stomatology, Nanjing University Medical School, Nanjing, Jiangsu, China.
3. Department of Periodontology, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China.