1. State Key Laboratory of Metal Matrix Composites School of Materials Science and Engineering Shanghai Jiao Tong University Shanghai 200240 P. R. China
2. Department of Oral and Cranio‐maxillofacial Surgery Ninth People's Hospital Shanghai Jiao Tong University School of Medicine Shanghai 200011 P. R. China
3. Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology Shanghai 200011 P. R. China
4. National Clinical Research Center of Stomatology Shanghai 200011 P. R. China