Before you take up plastic surgery via crowbar, let's eliminate every possibility of you or your wife making a mistake.
1.) Get a copy of everything that you signed. Review it carefully with an attorney.
2.) Get plenty of pictures of her mouth from before the operation, both on a regular camera and x-rays.
3.) Do the same for after.
4.) Go to the best dentist that you can find, and have him look over the papers and pictures to see if the dentist who performed the procedure had the right to (see step 1)
While doing this, don't freak out around her. Just go about your business as usual as best you can. Once you've cleared yourselves of blame, then get that same attorney to sue that dentist and/or chain for everything they're worth. Once the battle is over, get your daughter's mind checked to see if she's traumatized, and get care (therapy, meds, a big honking chocolate bar) if she needs it. All the while, make sure to not work as hard on other projects, and leave yourself time to relax so that you can focus on getting the legal stuff done slowly and deliberately. If all goes well and you win the suit, stash the money in her college fund so that she'll have some catharsis for what she's been through (don't mention to her too early, though).
-Penguin