1. Department of Operative Dentistry and Endodontics, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, China
2. Department of Conservative Dentistry, School of Dentistry, Kyungpook National University, Daegu, Korea
3. Department of Stomatology, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, China
4. Laboratory of Advanced Materials and Processes, Mechanical Engineering Department, University of Maryland Baltimore County, Baltimore, MD, USA
5. Department of Biostatistics, Medical College of Georgia, Augusta, GA, USA
6. Department of Stomatology, The First Hospital of Wuhan, Wuhan, China
7. Department of Oral Biology
8. Department of Endodontics, School of Dentistry, Medical College of Georgia, Augusta, GA 30912-1129, USA