Even in Canada, dental care is not covered, although many provinces provide basic care to low income household children. Employer health plans often cover it though.
I’d imagine why that’s why it’s such a stigma of the poor — it’s something that’s hard to hide that only money can solve. Just like how being plump was beautiful in an time when food was scarce, or being pale indicated you didn’t have to work in the fields, or being tanned now means you can afford time outside.
For some reason, discolored teeth bother me, while bad teeth don’t at all. I think it’s because I associate discoloration with cigarettes (or maybe because I have a slightly discolored tooth!)