So, in the recent comedy blockbuster "The Hangover" - which I just watched again last night with a buddy, God that was a damn funny movie. 
Anyway, spoilers ahead:
In the movie during the night they all forget Ed Helm's character, a dentist, pulled out one of his front teeth. He's missing the tooth throughtout the events of the entire rest of the movie -obviously.
We're occasionaly shown his mouth with the missing tooth, and we can note it missing as he talks.
So I'm wondering, how did they pull this off?
Is it like in "Dumb and Dumber" where Jim Carrey's character has a chipped front tooth (a dental injury Carrey aquired as a child, he had the chip re-bonded to the remaining tooth. He had this chip removed for making the movie to add to the character) so is the missing tooth an injury Helms sustained earlier in his life and had some-sort-of dental cosmetic correction undone for the movie role?
Or was there some fancy CGI work done here to make it look like his tooth was really missing?
"I look like a nerdy hillbilly."

Anyway, spoilers ahead:
In the movie during the night they all forget Ed Helm's character, a dentist, pulled out one of his front teeth. He's missing the tooth throughtout the events of the entire rest of the movie -obviously.
We're occasionaly shown his mouth with the missing tooth, and we can note it missing as he talks.
So I'm wondering, how did they pull this off?
Is it like in "Dumb and Dumber" where Jim Carrey's character has a chipped front tooth (a dental injury Carrey aquired as a child, he had the chip re-bonded to the remaining tooth. He had this chip removed for making the movie to add to the character) so is the missing tooth an injury Helms sustained earlier in his life and had some-sort-of dental cosmetic correction undone for the movie role?
Or was there some fancy CGI work done here to make it look like his tooth was really missing?
"I look like a nerdy hillbilly."