Um…I think you can infer why I’m asking. 
Husband’s dentures dropped one of the teeth and he swallowed it. It’s been 3 days and it hasn’t shown up in the stool. Since he’s got diverticulli (“pouches” in the intestine) I’m a wee bit worried it may be stuck in there, or…the question in the OP. Could it have been digested and not show up in the stool?
Well, what are the dentures made of?
Mind you, unless the answer is something like bone or real teeth, I think it is unlikely that it would get digested. I would assume most dentures are made of ceramic or maybe some sort of plastic. Those aren’t digestible.
On the other hand, unless you are carefully sieving through his stool, I should think something the size of a tooth could easily pass through without being noticed.
No idea. That’s why I put the question in GQ, where someone who may know can hopefully answer it.