1. Department of Prosthodontics, Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, PR China;
2. Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, National Clinical Research Center of Stomatology, Shanghai, PR China;
3. Engineering Research Center for Biomedical Materials of Ministry of Education, East China University of Science and Technology, Shanghai, PR China;
4. Key Laboratory for Ultrafine Materials of Ministry of Education, East China University of Science and Technology, Shanghai, PR China