1. Department of Clinical ResearchThe First Affiliated Hospital of Jinan University Guangzhou Guangdong 510632 P. R. China
2. Department of Oral and Maxillofacial & Head and Neck OncologyShanghai Ninth People's HospitalShanghai Jiao Tong University School of Medicine Shanghai 200011 P. R. China
3. Department of Oral and Maxillofacial SurgeryHainan West Central Hospital Danzhou Hainan 571700 P. R. China
4. Stomatology CenterTongji Hospital, Tongji Medical College, Huazhong University of Science and Technology Wuhan Hubei 430030 P. R. China
5. School of Public HealthXi'an Jiaotong University Health Science Center Xi'an Shaanxi 710061 P. R. China
6. Department of Human Anatomy, Histology and Embryology, School of Basic Medical SciencesXi'an Jiaotong University Health Science Center Xi'an Shaanxi 710061 P. R. China