system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What did people do before the inventions of toothbrushes?

It seems like if people nowadays don’t brush their teeth often, they diminish and rot until they fall out. Before the toothbrush was invented, did people just lose all their teeth by their 20s? And how do animals teeth stay clean?
gpt
Don't forget that before 100 years ago, diets had much less sugar in them so there were few if any cavities.  No cavities generally mean healthy teeth that didn't fall out.  They probably had horrible bad breath and staining, but the teeth had much less caries (cavities) in them.

Twigs were used to rub teeth clean as were finger with salt or seaweed as abrasive.