1. Department of Periodontics and Oral Mucosa, Affiliated Stomatology Hospital, Southwest Medical University, Luzhou, Sichuan 646000, P.R. China
2. Department of Orthodontics, Mianyang Stomatological Hospital, Mianyang, Sichuan 621000, P.R. China
3. Department of Oral Pathology, College and Hospital of Stomatology, Hebei Medical University and The Key Laboratory of Stomatology, Shijiazhuang, Hebei 050000, P.R. China
4. Department of Nephrology, Second Hospital, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China
5. Department of Oral Medicine, Second Hospital of Hebei Medical University, Shijiazhuang, Hebei 050000, P.R. China