1. Department of Periodontology, School and Hospital of Stomatology, Cheeloo College of Medicine, Shandong University & Shandong Key Laboratory of Oral Tissue Regeneration & Shandong Engineering Laboratory for Dental Materials and Oral Tissue Regeneration, Jinan, Shandong, China
2. Department of Endodontics, The Affiliated Hospital of Qingdao University, Qingdao, China
3. School of Materials Science and Engineering, China University of Petroleum (East China), Qingdao, China