1. National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041, China
2. State Key Laboratory of Oral Diseases, Sichuan University, Chengdu, Sichuan 610041, China
3. Department of Periodontology, West China College of Stomatology, Sichuan University, Chengdu, Sichuan 610041, China