It’s something to worry about that I’ll bet you never guessed you needed to worry about:
Brushing your teeth may cause cavities!
Didn’t see that one coming, I’ll bet. You are taking a big risk every single time you brush your teeth! You are, in fact, brushing the cavities right in.
And if you do “brush cavities into softer parts of teeth” you will see a giant, angry tooth staring back at you from the mirror. And boy, is it ever not happy with you. You’d better start using Teel before it jumps out and starts biting.
From Life, September 21, 1942; big version here.