1. Department of Stomatology, Xiangya Hospital, Central South University, Changsha, Hunan, P. R. China
2. Research Center of Oral and Maxillofacial Tumor, Xiangya Hospital, Central South University, Changsha, Hunan, China
3. Institute of Oral Precancerous Lesions, Central South University, Changsha, Hunan, China
4. Department of Vascular Surgery, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China