[linopolus]

> If nature could fix everything with no intervention we wouldn't need to brush our teeth either.

Well, I'm not saying nature actually can fix everything, but in case of toothbrushing, it's dependent on your diet. There are peoples knowing nothing of brushing, but they feeding themselves different than we "civilized" people are.

[emodendroket]

Walking primarily on paved sidewalks isn't really natural either.

Apparently even cavemen did make some effort to clean their teeth (and according to this article, monkeys still do): https://www.washingtonpost.com/news/speaking-of-science/wp/2...