1. Department of Stomatology; Xiangya Hospital; Central South University; Changsha 410008 People's Republic of China
2. Department of Biomedical Engineering; College of Biology; Hunan University; Changsha 410082 People's Republic of China
3. Department of Materials Science and Engineering; College of Materials Science and Engineering; Beijing University of Chemical Technology; Beijing 100029 People's Republic of China
4. Department of Orthodontics; Xiangya Stomatological Hospital; Central South University; Changsha 410008 People's Republic of China
5. Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences; Shenyang 110016 People's Republic of China