1. School
and Hospital of Stomatology, Tianjin Medical University, Tianjin 300070, People’s Republic of China
2. Beijing
Laboratory of Biomedical Materials, Beijing University of Chemical Technology, Beijing 100029, People’s Republic of China
3. Department
of Geriatric Dentistry, Peking University School and Hospital of Stomatology, Beijing 100081, People’s Republic of China
4. School
of Materials Science and Engineering, Tianjin University, Tianjin 300072, People’s Republic of China