I’m American, but I’ve lived in several different countries pretty much my whole life.
Culturally, America is a little weird about keeping up appearances no matter the cost. That’s not exclusively an American thing, obviously, but in my experience, we’re the absolute worst at this. People will do absolutely, wildly insane and irresponsible shit to make sure they look like they have their shit together, including getting into debt. Again, I know this all happens overseas too, but everything is louder, flashier, bigger here, and so is this.
One of the biggest cultural problems that we have is the deeply ingrained idea that poverty is the result of poor choices, stupidity, etc. — and when I say “deeply ingrained”, I mean deeply ingrained. Most people don’t even realize that they feel that way, and even people who are poor through absolutely no fault of their own may believe deep down that it is their fault and they’re worthless or stupid etc. Once again, the idea that people are poor because they make bad choices is not uniquely American by any stretch of the imagination, but it’s orders of magnitude more deeply ingrained and pervasive here, so much so that just looking like you’re poor in can ruin your chances in life.
What does that have to do with teeth? Well, they’re an indicator of socioeconomic status here. I have a snaggle tooth that I’m only self-conscious about when I’m here. People notice, they will literally avert their eyes when they see it, and I instinctively hide it to the point of avoiding smiling altogether. When I’m in Japan, or Ireland (or really anywhere in Europe), not only do I not feel self-conscious at all, but it’s not hard to find other snaggle-toothed people, all smiling without a care in the world. As long as your teeth aren’t rotten or something, nobody seems to care.
Every time I’ve been to the dentist in the US, they’ve mentioned that tooth like it’s a problem that needs to be corrected, even though there’s nothing wrong with it other than the fact that it’s not straight like my other teeth. They offer braces, extractions, all kinds of shit. I keep my mouth very clean and I’ve never had a cavity in my life (I’m 42), I just have this one weird lil tooth.
When I go to the dentist overseas, they never really bring it up. They check my teeth for cavities etc. compliment my oral health, and send me on my way. The only time a non-American dentist brought it up was when he asked if it was hurting my upper lip or anything of that nature. No one outside the US ever treated it like it was a health issue that needed correction or offered me unsolicited advice for correcting it. (Disclaimer: a snaggle tooth CAN cause health problems if it makes it difficult to clean your mouth etc, but mine doesn’t — please don’t use my words as an excuse not to address issues that may be damaging your oral health).
TLDR: anything other than perfectly straight teeth makes Americans think you’re poor and being poor means you’re lazy/dumb/whatever therefore you must fix it regardless of cost. So it’s a huge industry here.