I had this same problem happen to me when I was younger. Pretty much all my front teeth had this issue. My baby teeth needed to be pulled to make room for the teeth to go/try to go into their correct spot (and I literally mean, pulled. They weren't loose). Once the dentist knew the top eye teeth (or bottom eye teeth or whatever tooth was poised to come out next) were visble on the x-ray film, I was in there getting the baby teeth pulled so the adult teeth could come through. My mouth was too small for my teeth, so they didn't have any choice but to pull baby teeth as my adult teeth came in. My teeth would have been in MUCH worse shape if they hadn't done the pulling.
Today, the top eye teeth are a little slanted and jut out a bit from the front teeth, and the bottom eye teeth sit a little behind the front teeth and the teeth next to them. (They had all literally been sitting north to south in my mouth instead of the usual east to west orientation.) And that's GOOD, after having had braces and retainers. All the other teeth are perfectly lined up because the dentist pulled the teeth as the next adult teeth were shown to be coming in/through on the X-ray.
When I was a teenager (I think 13), I wore braces to pull my front teeth into alignment because they were quite crooked because of coming in before their time. I know they usually do braces a lot younger these days. I wore mine for about 2 years and then had a removable retainer on the top and a permanent one on the bottom until I had my wisdom teeth removed in college. All 4 eye teeth had to do A LOT of moving to get to the point where they're fairly straight today. In fact, my orthodontist praised my childhood dentist for the work he'd done on my teeth. He said that with my type of mouth he usually sees teeth a whole lot worse than mine come in for braces--and braces can only do so much.
I just read the post about a jaw expander--wow. I don't remember there being anything like that when I was younger. That's actually a neat concept. I wonder if something like that would have worked for my mouth.
And the way my teeth came in/were pulled, I actually didn't have any issues with brushing or flossing and didn't have any cavities on the front teeth. My cavities were confined to my 6 year molars.