1. Department of Bone Metabolism, School of Stomatology, Shandong University, Shandong Provincial Key Laboratory of Oral Tissue Regeneration, Jinan, Shandong 250012, P.R. China
2. Department of Endodontics, Jinan Stomatological Hospital, Jinan, Shandong 250012, P.R. China
3. Department of Developmental Biology of Hard Tissue, Graduate School of Dental Medicine, Hokkaido University, Sapporo 060‑8586, Japan
4. Department of Oral Maxillofacial Surgery, School of Stomatology, Shandong University, Shandong Provincial Key Laboratory of Oral Tissue Regeneration, Jinan, Shandong 250012, P.R. China