system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:Prior to toothpaste being introduced to the world, how did humans of the past maintain oral hygiene?
gpt
They died before it mattered. Their diets had far less sugar in it, so their teeth didn't wear as fast, and they had fewer cavities to deal with. By the time they started losing teeth, they were probably already old and close to dying anyway. As modern medicine started increasing the expected lifespan, dentures were created to make up for lost teeth.

As well, fluoride is a naturally occurring mineral found in pretty much all water sources. That's actually how it was discovered that fluoride helps your teeth - scientists were studying the effects of high levels of fluoride in the drinking water of people in the mountains. So most people were exposed at least to *some* fluoride to help remineralize their teeth as they were worn down.