1. Restorative Dental Sciences, Endodontology, Faculty of Dentistry, The University of Hong Kong, Hong Kong 999077, SAR, P.R. China
2. Department of Implant Dentistry, The Affiliated Stomatological Hospital of Xuzhou Medical University, Xuzhou, Jiangsu 221002, P.R. China
3. School of Stomatology, Peking University, Beijing 100081, P.R. China
4. Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical University, Xuzhou, Jiangsu 221004, P.R. China