1. State Key Laboratory of Oral Diseases; National Clinical Research Center for Oral Diseases; Department of Endodontics; West China Hospital of Stomatology; Sichuan University; Chengdu China
2. State Key Laboratory of Oral Diseases; National Clinical Research Center for Oral Diseases; Department of Orthodontics; West China Hospital of Stomatology; Sichuan University; Chengdu China
3. Division of Endodontics; Department of Oral Biological and Medical Sciences; Faculty of Dentistry; University of British Columbia; Vancouver BC Canada