1. Department of Oral Surgery, Stomatological Hospital , Southern Medical University , Guangzhou , P.R. China
2. Department of Endodontics, Stomatological Hospital , Southern Medical University , Guangzhou , P.R. China
3. BGI Genomics, BGI-Shenzhen , Shenzhen , P.R. China
4. Shenzhen Key Laboratory of Human Commensal Microorganisms and Health Research, BGI-Shenzhen , Shenzhen , P.R. China
5. Laboratory of Genomics and Molecular Biomedicine, Department of Biology , University of Copenhagen , Copenhagen , Denmark
6. School of Medicine , South China University of Technology , Guangzhou , P.R. China