I have accidentally swallowed a piece of broken denture without realizing it...but almost 98% of the denture still remains in my month ......am really worry but am noting feeling any pain for now...is 24hrs?

In all likelihood it will pass. If you need to recover poop into a bowl and strain it with a strainer. Start now.

It should pass right through, but there is a very small chance that it can get stuck or even do damage if it's sharp. Cannot be seen on an x-ray, so you will have to do detective work. You will have to capture and strain your feces every day until you find that the piece has safely passed. If no success in a week, see your Physician.