1. Department of Endodontic and Operative Dentistry; Tianjin Stomatological Hospital; Tianjin China
2. State Key Laboratory of Oral Diseases; Sichuan University; Chengdu China
3. Department of Oral Biology; School of Dentistry; University of North Carolina at Chapel Hill; Chapel Hill NC USA
4. Department of Periodontology; Guangdong Provincial Key Laboratory of Stomatology; Guangzhou China
5. Department of Endodontic and Operative Dentistry; West China Hospital of Stomatology; Chengdu China