1. Department of Periodontology Hospital of Stomatology Jilin University Changchun 130021 P. R. China
2. State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied Chemistry Chinese Academy of Science Changchun 130022 P. R. China
3. Key Laboratory of Superlight Materials and Surface Technology Ministry of Education College of Materials Science and Chemical Engineering Harbin Engineering University Harbin 150001 P. R. China
4. Dental Health Department College of Applied Medical Sciences King Saud University Riyadh 12372 Saudi Arabia