Those bleeding bacteria – without them there would be no gum disease.

Without the bacteria there would be no life at all.

One of the objects of chewing food is to cut and squash it into smaller pieces so that can be swallowed. Another object is to mix something into the food to start dissolving it. That something is bacteria – they initiate digestion. They are also crucial for maintaining oral as well as general health. “Little living animalcules prettily moving” is how they were described when they were first studied in around 1674.

The bacteria are naturally good at sticking to things because they are required to stick to the food as it is being chewed. To dissolve the food they are designed to stick to the bacteria release chemical onto it.

It is due to a consequence of their natural function that the bacterial also stick to teeth and that they release chemicals onto the gums, breaking them down; bad breath is often a side-effect of gum disease. The gums react by initiating a process designed to release defensive chemicals, bleeding from the gums is the first sign of this inflammatory reaction taking place.

Hopefully, it makes sense that the object of oral hygiene is not to reduce the overall number of bacteria per se but to remove the ones that have become stuck to the tooth surfaces and the gum margins.