1. State Key Laboratory of Oral Diseases, Sichuan University Chengdu 610041, China
2. Department of Prosthodontics, West China School of Stomatology, Sichuan University, Chengdu 610041, China
3. Department of Periodontics, the Affiliated Stomatology, Hospital of Chongqing Medical University, Chongqing 400015, China
4. School of Dentistry, Tianjing Medical University, Tianjing 300070, China