1. Department of Orthodontics, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, China
2. Department of Orthodontics, Stomatology College of Qingdao University, Qingdao, Shandong, China
3. Department of Stomatology, The Affiliated Qingdao Municipal Hospital, Qingdao University, Qingdao, Shandong, China
4. Department of Nursing and Hospital Infection Management, The Affiliated Hospital of Qingdao University, Qingdao, China
5. Department of Stomatology, Chinese PLA General Hospital, Beijing, China