1. The Second Clinical College of Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, P.R. China
2. Department of Stomatology, Guangzhou Women and Children's Medical Center, Guangzhou, Guangdong 510000, P.R. China
3. Department of Laboratory Medicine, The Affiliated Hexian Memorial Hospital of Southern Medical University, Guangzhou, Guangdong 511400, P.R. China