1. Stomatology Hospital, School of Stomatology, Zhejiang University School of Medicine, Hangzhou 310006, P. R. China
2. Zhejiang Provincial Clinical Research Center for Oral Disease, Hangzhou 310006, P. R. China
3. Key Laboratory of Oral Biomedical Research of Zhejiang Province, Cancer Center of Zhejiang University, Hangzhou 310006, P. R. China
4. Union Hospital, Tongji Medical College, Department of Stomatology, Huazhong University Science & Technology, 1277 Jiefang Ave., Wuhan 430022, Peoples R. China