1. Department of Implantology, School and Hospital of Stomatology, Shandong University, Shandong Key Laboratory of Oral Tissue Regeneration and Shandong Engineering Laboratory for Dental Materials and Oral Tissue Regeneration, Jinan, Shandong 250012, P.R. China
2. Department of Prothodontics, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, Zhejiang 325027, P.R. China