I'd prefer to draw them without, but then how could they chew? Birds generally swallow things whole. And some birds are drawn with pliable beaks, which I'd also prefer not to draw, but then that complicates the whole talking thing. Of course it could be argued that wolves and dogs and foxes couldn't really talk either, and then there's the matter that some birds do talk, but I'm not entirely sure how.
Furry porn involves more suspension of disbelief then your average sci-fi movie.
they have tiny spines that rest pointing down into the mouth. (see: penguins) not all birds have them, but most have them farther back inside their beak (near the throat) so i wouldn't worry about drawing them.
if this is a gryphon, give it a canid/felidae lower jaw that just comes under the beak with fangs.
and the birds that talk have developed high controll of their larynx and other muscles near their vocal flaps. they use their tongue to whistle, they don't technically 'talk' in the way we do.
Go for the "magic teeth" route, much like the "magic hand" in which a character usually has a rounded lump at the end of their arm, and will only ever be a hand if they need to point or pick up something. It's an artistic choice, they only appear when needed.
This is in fact my approach to most problematic character designs. Particularly the problem that I love suit vests and draw them on everyone, but they can't be worn by someone with wings. So I never draw a winged guy with a vest on from the back.
Actually, winged characters can wear waistcoats/vests. Do a Google for Backless Waistcoat, they're a fairly common formal piece, usually worn at weddings and the like under a suit so nobody is any the wiser. Not keen on them myself since I like my layers, but they're popular with hire companies for their one-size-fits-all nature.
I say go the cartoon logic route and make them toothless by default, then give them magically-appearing teeth when they're needed for an expression or something.
Furry porn involves more suspension of disbelief then your average sci-fi movie.
Also, don't some raptors have teeth? So yes, depending on the bird and, more importantly, how it looks when drawn.
if this is a gryphon, give it a canid/felidae lower jaw that just comes under the beak with fangs.
and the birds that talk have developed high controll of their larynx and other muscles near their vocal flaps. they use their tongue to whistle, they don't technically 'talk' in the way we do.
I never draw teeth on the Corb though SO
how's your weight and all now? :P
and teeth can be acceptable on birds on the given situation, usually comical