1. Department of Stomatology, Guangzhou Hospital of Integrated Traditional and West Medicine, Guangzhou, Guangdong 510800, P.R. China
2. Department of Stomatology, Hainan General Hospital, Haikou, Hainan 570102, P.R. China
3. Department of Stomatology, Shenzhen Hospital of Guangzhou University of Chinese Medicine (Futian), Shenzhen, Guangdong 518034, P.R. China