A metal detector is one way to track a screw's progress without further radiation - though while kids are still in diapers it's easy (if not pleasant!) to know pretty well whether or not it has passed.

Plenty of fluids - and things that speed up poops like those you've suggested - may help: but you don't want laxatives that increase intestinal contractions.

How long it will take varies quite a bit, but when something hasn't passed in a week or so, it's a good idea to check back in with your doc.