Yeah, about that ...
In Sweden at the turn of the 20th century, some scientists were tasked with finding a solution to the country's crippling tooth-decay problem. The reason Sweden doesn't rate highly on your list of countries with discouraging oral hygiene is because they succeeded, but not without some questionable methods. You see, Sweden's top dental professionals trolled the local mental hospitals for research subjects to set up a 10-year study into the source of tooth decay, because back then "informed consent" wasn't extended to people with "brain fever" or "the gibbering babble-spooks." Crazy people were treated like training dummies for the medical community, among anything else a random person paid enough money to use them for (see "pathological asylum orderlies," above).
"Suppose I wanted to lash two or three together into a toboggan -- how much would that run me?"
The Swedish scientists had a sus**cion that tooth decay was directly linked to sugar consumption, so to test this theory, they injected a massive amount of sugar into the diets of their completely unwilling and mentally deficient research subjects, to watch how it destroyed their teeth. The researchers fed their subjects candy and soda and even spiked their bread with sugar to speed up the rate at which their teeth rotted into gooey, black sponges dangling stinkily in their crazy heads.