The Tooth, The Whole Tooth, And Nothing But The Tooth

When you hear or see the word "microbiome," there's one part of the body that immediately comes to mind: the gut. Those billions and billions of bacteria living in your gut are usually the star of the health show, but today, let's turn the spotlight someplace else. A different microbiome, underappreciated and unloved.

This is the story of our mouth microbiome. Or, more accurately, a history.

The new research asked a pretty simple question: How did our ancestors' mouths differ from those in the modern day? To answer this question, the researchers performed a genomic analysis of a pair of teeth taken from a man who lived in Ireland 4,000 years ago, during the Bronze Age.  

To no one's surprise, the consensus is that the man's dental microbiome at the time of death was not exactly healthy, and in fact he was at high risk for developing cavities. Hey, let's see you have a healthy mouth when you live in a society without toothpaste. It did exist at this time, but not in Ireland. 

While the poor shape of the man's mouth isn't a shock, the reason behind it is rather interesting, as the teeth were rich in Streptococcus mutans, a bacteria very well known as a major contributor to tooth decay. Now, this doesn't sound like it should be a surprise, considering the aforementioned lack of toothpaste, but other ancient mouth microbiomes do not show nearly as much S. mutans. It's actually very rare to see this bacteria in people living before 1500 AD. 

In our Irish friend's case, the S. mutans had done such a thorough job taking over his mouth that other, more beneficial streptococcal species were basically absent. That said, there were plenty of other bacteria species in the sample. So many, in fact, that the ancient microbiome was more biodiverse than modern-day mouth microbiomes. In a lot of ways, ancient teeth were healthier than ours, mostly down to the lack of sugar in their diets compared to ours.

So, if you think you could pluck a person out of ancient history and they'd have a smile like this, think again. All our Irish friend needed was ye olde dentist, which is something pretty much everyone over on the British Isles need. Yeah, we're ending with a "British people have bad teeth" joke. You knew it had to happen.