Wenqing Zhang1, Qinghua Mao2, Xin Lyu3, Hong Hua1, Zhimin Yan4. 1. Department of Oral Medicine, Peking University School and Hospital of Stomatology, Beijing 100081, China. 2. Department of Oral Medicine, Peking University School and Hospital of Stomatology, Beijing 100081, China; Department of Oral Medicine, The Affiliated Stomatology Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China. 3. Department of Oral Medicine, Peking University School and Hospital of Stomatology, Beijing 100081, China; Department of Oral Medicine, Beijing Stomatological Hospital, Capital Medical University, Beijing 100050, China. 4. Department of Oral Medicine, Peking University School and Hospital of Stomatology, Beijing 100081, China. Electronic address: yzhimin96@163.com.