It's a really unfortunate historical accident, especially in the US.

Dentistry evolved relatively late compared to regular medicine, and early oral procedures were mostly tooth extractions, which ended up being predominantly done by barbers, who would also do surgery (!). These procedures were often considered crude and beneath that of a trained doctor, and they were generally performed by self-trained practitioners. There were several attempts in the 1800s to integrate dentistry into mainstream medicine, but they failed, both because the doctors of the time didn't think of dentistry as being a real science, but also because, as dentistry started to legitimize itself, the dentists themselves preferred being separate.

For some reason the same separation also evolved in the U.K., but it's more integrated in other countries. For example, basic dental coverage is part of national healthcare in Germany and Japan. In the U.S., dentists have their own schools and licensing boards and so on, which isn't the case in the rest of the world, where dentistry is usually accepted as a regular branch of medicine and taught at the same universities.

Nor your eyes for some reason either.

Here's an article about the history of that:

https://www.nbcnews.com/better/health/reason-your-dental-wor...

Yes, it would help to know that I could see a dentist who would inform me of cavities and gingivitis that I am (or am not, depending on genes), developing as a result of my brushing habits (and through that feedback help refine said habits), rather than merely hoping and doing nothing more for lack of funds.

And many people will require regular teeth cleanings to avoid gum pockets and consequent gingivitis despite their best efforts at brushing and flossing.

There are other situations where tooth infections can move to the brain in a matter of days, risking death if left untreated. Regular checkups reduce that risk considerably.

The other side of your argument would imply that the existence of toothpaste renders the entire field of dentistry inessential.

It is the initial purpose of a microbiome to be at least commensal, in that it is usually prohibitively expensive to maintain a sterile environment so the odds of a true pathogen colonizing a system is greatly reduced if you simply have a crowded space of neutral participants.

Once that's true it does seem there's a lot of host and microbiome interactions we've only begun to explore, but it shouldn't be surprising that co-evolution of the microbiome and host begins to take over as soon as you have one. One great example is short-chain-fatty-acid (SCFA) producing bacteria in the human gut. [1] These seem to be essential, and if there was a general takeaway to improve health, it would be to eat your roughage so they can do their job.

This is also why high alpha-diversity (community richness in particular) is such a dead-ringer for healthy vs diseased states. And frustratingly, is often exactly where the story ends for a lot of observational studies.

Also, in case you are curious, artificially sterile mice (gnotobiotic mice) tend to act differently than other mice, which is pretty odd to be honest, and why the gut-brain axis is a plausible mechanism to research further. [2]

[1]: https://pmc.ncbi.nlm.nih.gov/articles/PMC10180739/ [2]: https://www.sciencedirect.com/science/article/pii/S088915912...

Just like the gut you have to have the right bacteria. Not none. This is a study on Psoriasis which is caused by systematic inflamation.

https://pmc.ncbi.nlm.nih.gov/articles/PMC9076720/