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authors read and approved the final manuscript.”
“Background In the oral cavity, bacteria encounter many different stress factors. Shear-forces see more and high flow rates of saliva dominate on exposed surfaces, while bacteria colonizing the gingival crevices and/or subgingival pockets have to contend and withstand with the host’s immune response. As in most other environments, bacteria form biofilms as protection from these harsh conditions . The bacterial community colonizing the oral cavity is highly complex and varies considerably between different individuals. According to current reports, 600 to 700 established species and likely several thousand only partially cultivable taxa can be detected . However, this consortium does not pose a threat to a healthy individual. It even has a protective function by preventing the establishment or predominance of harmful organisms . Several factors like imbalanced nutrition, smoking, diabetes, emotional stress, or genetic predisposition  can lead to changes in the composition of this subgingival community, leading to a loss of the natural ecological balance. Potentially pathogenic species may increase in numbers, starting to cause persistent infections of host tissues that are capable to cause not only tooth loss and bone resorption but also can spread out to extra-oral sites and become systemic .