1. Stomatology Hospital School of Stomatology Zhejiang University School of Medicine Zhejiang Provincial Clinical Research Center for Oral Diseases Key Laboratory of Oral Biomedical Research of Zhejiang Province Cancer Center of Zhejiang University Engineering Research Center of Oral Biomaterials and Devices of Zhejiang Province Hangzhou 310000 P. R. China
2. Zhejiang Key Laboratory of Plastic Modification and Processing Technology College of Materials Science & Engineering Zhejiang University of Technology Hangzhou 310014 P. R. China
3. The Wallace H. Coulter Department of Biomedical Engineering Georgia Institute of Technology and Emory University Atlanta GA 30318 USA