In one of the picture threads I found a guy who takes absolutely amazing photos of his fish! I would pay him good money to come here and take photos of mine!
He has one closeup photo of a Betta with his mouth open and you can clearly see the rows and rows of little teeth on the top of his mouth. That's how they crunch their pellets.
Scroll down about 3/4 of the way to see the Betta teeth photo. All his photos are amazing!