I wonder how this goes for biting the nails too. I don't think it comes from a single place or anything but it seems like it'd be just as commonplace as it is today.

This thread from the FAQ might be helpful:

[What did people use before the invention of the toothbrush, floss and scissors?] (https://www.reddit.com/r/AskHistorians/comments/12m6x7/what_did_people_use_before_the_invention_of_the/)