"Acrylic teeth, the kind used to make dentures, come in little plastic trays, separating the top, bottom, front and back teeth. Very pratical; you don't have to guess which tooth goes where (although mouth anatomy is fairly simple).
I bought mine on ebay; it cost about 20$ including shipping from china, and I have 6 complete sets of teeth."
I never would have thought to source choppers like this. In hindsight it's obvious the ones used for dentures had to come from somewhere. It just never occured to me that full sets of human teeth were so cheap and easy to get.
These would be ideal for all kinds of gaffs and faux specimens. In the past commenters have mentioned how creepy it is to see a non-humanoid creature with human teeth. You could create some very disturbing dentition with a full set or mix and match incisors, molars, and canines for a more inhuman look.