I've been giving Rose DentaStix, one every other day. Her teeth have never looked better. DentaStix seem to be a LOT easier to chew than the greenies were, and she likes them a whole lot better. They sell them @ PetsMart.
Hope your baby feels better.
Funny story, Rose had that problem recently (screaming guts--I know exactly the sound you mean!). DBF's daughter said it sounded like she swallowed the cat!