Still think better graphics are everything?

That tongue is teeth coloured

Have you ever been in his mouth

Have you ever seen Kirby chew before swallowing?

Maybe he chews when he tries to be civilized
EDIT: Hooooooooold up I remember a cutscene in a kirby game where he sat down and chewed a food like a normal human would. I can't remember if it was an apple or a cake, but he definitely used teeth there. Imma do some digging and see if I can find it

It changes. In some of the manga he's depicted with teeth and he has teeth in the North American commercial for Kirby's Dream Land. But in A Dental Dilemma they find that Kirby acts like he has a toothache but doesn't actually have any teeth