There are many kinds of bacteria, viruses and funguses that call the mouth home, such as Fusobacteria, Proteobacteria, Actinobacteria, Chlamydiae, Chloroflexi, Bacteroidetes, Spirochaetes, SR1, Firmicutes, Synergistetes, Saccharibacteria, and Gracilibacteria, and they all live in harmony, until something becomes unbalanced, causing oral infections and nasty diseases