1. Department of Stomatology, Guangzhou Women and Children’s Medical Center, Guangzhou, Guangdong 510623, P.R. China
2. Department of Periodontics, Stomatological Hospital, Southern Medical University, Guangzhou, Guangdong 510280, P.R. China
3. Department of Oral and Maxillofacial Surgery, Stomatological Hospital, Southern Medical University, Guangzhou, Guangdong 510280, P.R. China