Recently I surprised my English friends by getting braces fitted to straighten my teeth. "Cosmetic" dentistry like this was rare enough among children when I grew up in England, let alone adults entering the second half of life (if I'm lucky -- last third of life if family history is any guide...).
The explanation is quite simple: I've been trying to pass the test to become a US citizen. At my first attempt I passed the oral exam easily, but failed the dental exam. If I want to become naturalized, I'm afraid I'm going to have to bring my teeth up to American standards.