That's one of the theories. But it was never stated how many she had left and how many it took to cure him and restore his regeneration ability.
Another theory is that the change from Patrick Troughton to Jon Pertwee having been forced on the Doctor by the Time Lords wasn't actually a regeneration. That would only add 1 though.
Now there's a rumor that Matt Smith may have a role in the next Star Wars film.
Since I don't have access to BBC America I have to avoid any sites that might spoil the anniversary special after tomorrow, until I receive the DVD in December. Doctor Who: The Last Day mini episode
- probably the last prequel to The Day of the Doctor
The Day of the Doctor 3D is having a second showing in theaters Monday night, including one locally. I ordered my ticket online.
EDIT: Just got back from The Day of the Doctor. Enjoyed it. I wasn't expecting
a cameo by the Peter Capaldi Doctor or Matt Smith's Doctor to meet Tom Baker. That scene has some people confused. Since of course its Tom Baker now, white hair, not Tom Baker 1970s curly brown hair.
The 3D effect actually worked. At on point I ducked because an explosion sent a piece of metal flying at my head
Before the 3d theater version of The Day of the Doctor, there was a short film featuring Strax explaining what happens to criminals who use their communication devices or talk loud during the film. Then a short film in which Matt Smith welcomes the audience to the 100th Anniversary Special featuring all 57 Doctors. When corrected he apologizes for confusion as he just came from the future. After the film there was a short making off special.
A couple of short video clips that appeared on November 23rd before the special aired: A message from Strax - The Day of the Doctor An announcement from the Doctor