Oh, wow! This makes me wonder if tooth powder was originally more common and toothpaste a more modern thing.
I think so. My grandparents always used tooth powder and had all their teeth in their 80s. When I tried to find tooth powder (prior to the internet) it was not available anywhere. Multliple recipes for making your own tooth powder are online. I advise against using a recipe with charcoal as it looks disgusting and no one would use it except me. Sometimes I just use baking soda which tastes bad, but you could add powdered xylitol.