When did people start brushing their teeth? What did humans do before that to upkeep dental health?

The first recorded toothbrushes were called chew sticks and date back to ancient babylonian societies circa 3500 bc. The greeks and romans used dental picks which are somewhat akin to a reusable toothpick. The first bristle brush toothbrush comes from Qin dynasty china. Toothpaste comes from the greeks and romans and was made with oyster shell among other things. The reason dental care came about so early was the switch from meats to grains as staple foods, which much more rapidly decays teeth. Interestingly, according to new research, the people of the Sudan used purple nutsedge to delay tooth decay. Short article on that tidbit here: http://www.smithsonianmag.com/smart-news/ancient-tooth-plaque-shows-our-ancestors-used-feast-weeds-180952079/