1. Department of Emergency, Affiliated Hospital of Weifang Medical University, Weifang, Shandong 261031, P.R. China
2. Department of Stomatology, Affiliated Hospital of Weifang Medical University, Weifang, Shandong 261031, P.R. China
3. Department of Public Health, Affiliated Hospital of Weifang Medical University, Weifang, Shandong 261031, P.R. China