1. Department of Periodontics and Oral Medicine; School of Stomatology, Fourth Military Medical University; Xi'an China
2. Department of Stomatology; Affiliated Hospital of the Academy of Military Medical Sciences; Beijing China
3. Department of General Surgery; Xijing Hospital, Fourth Military Medical University; Xi'an China
4. The Interdisciplinary Nanoscience Center (iNANO), Department of Molecular Biology and Genetics; Aarhus University; Aarhus Denmark