[No Blue States]

"Hlusko spent 8 hours grinding a piece of grass along a tooth taken from a baboon. She then replicated the experiment for 3 hours on a modern human tooth"

Man 11 hrs of doing that cant be much fun.. Im sure early people picked their teeth, and with whatever was handy to get that jerky unstuck. And probably not as a custom but because like to us it bothersome.. I would think a small broken twig with a sharp end would work fine. Heck they may have even flossed with sinew.. these 11 hrs outside would have been better spent looking for a T-Rex head or paleo points.

[RightWhale]

The women would floss while sitting around the hearth gossiping about each other. Day after day gossiping, flossing. Flossing, gossiping. The men would floss while lurking in ambush for their next victim dinner.