Figure 4. The “core microbiome” of the age groups in the three sites. (A) The “core microbiome” of various age groups at the genus level. (a) GCF; (b) SAL; (c) TB. (B) The “core microbiome” of various age groups at the species level. (a) GCF; (b) SAL; (c) TB. (C) The “core microbiome” of the three oral cavity sites with age at the genus level. (a), genus level; (b) species level.