stuck to it

“My false teeth are stuck to it.”
What is the meaning of it?

Presumably whatever is being eaten is so sticky that the teeth get caught on it.

I’m not aware that this means anything more than what it literally says.

However, what is the full context? Does it appear to have a non-literal meaning?

This seems to be the punchline of a joke. One version that I found reads:

A man at the movies was down on his knees between the seats, running his hand along the floor by the feet of others. The usher rushed down to find out what was going on. He asked, “What are you looking for?” The man replied, “I’ve lost my chewing gum”. “And why is that so important?” asked the usher. He answered, “My false teeth are stuck to it.”

Your story is fine.
What is the meaning for ‘usher’ in this context?
Is it the man sitting next to him (who lost his false teeth) ?

The usher is the cinema attendant. The person who collects tickets and traditionally showed people to their seats.