For anyone in the Uk or elsewhere who has access to the BBC iplayer radio catch-up service on the Internet, the Jeremy Vine programme BBC Radio2 at lunchtime today (31st August) somewhere between 12pm and 2pm had a discussion with a dentist and then phone-in comments about adults with braces.
Quite a bit of detail about the various types and encouragement to get work done, no matter what age.
Jeremy himself explained that he had had braces in the past and also commented on the differences between the preferences of those in the US and the UK  for different final outcomes / looks.
He felt that Americans preferred a wider smile and therefore more of a tendency towards palatal expanding etc.

May be worth a listen if you can find it.