1. State Key Laboratory of Oral Diseases; West China Hospital of Stomatology; Sichuan University; Chengdu Sichuan P. R. China
2. Department of Stomatology; Daping Hospital and the Research Institute of Surgery of the Third Military Medical University; Chongqing P. R. China
3. Department of Oral Medicine; West China Hospital of Stomatology; Sichuan University; Chengdu Sichuan P. R. China
4. Department of Oral Medicine; Qingdao Stomatological Hospital; Qingdao Shandong P. R. China