1. Department of Endodontics, Stomatological Hospital, School of Stomatology, Southern Medical University, Guangzhou, China
2. College of Stomatology, Southern Medical University, Guangzhou, China
3. Foshan Stomatological Hospital, Foshan University, Foshan, Guangdong, China
4. School of Material Science and Engineering, South China University of Technology, Guangzhou, China