1. State Key Laboratory of Oral Diseases and National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Chengdu, China
2. Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
3. Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China
4. Department of Endodontics, College of Dentistry, University of Illinois at Chicago, Chicago, IL, USA
5. Clinical Research Center for Oral Diseases of Sichuan Province, Chengdu, China