1. Department of Periodontology, The Second Affiliated Hospital of Zhejiang University, School of Medicine, Hangzhou 310009, P.R. China
2. School of Materials Science and Engineering, Zhejiang University, Hangzhou, Zhejiang, 310027, China
3. Facility for Histomorphology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310027, China
4. Department of Biomedical Engineering, The Chinese University of Hong Kong, Hong Kong SAR, China