All I'm trying to do is figure out the heighth of the platform I will need to build to install a new shower stall. Oh and Marlin, I said that a hole was not an option for many reasons. Number one on that list is not wanting to turn a $3,000 job into a $30,000 job.
In brief: Generally.. As far as the filling itself goes, you can eat right away with tooth colored composite fillings, but should wait at least one hour with amalgam (silver) fillings. It's always best you ask your own dentist as this can vary somewhat based upon the size and location of the filling.
If it is a bonded composite (white) filling you don't really have to wait at all. If they made you numb i would wait at least until the numb feeling goes away so you do not accidently bite yourself. If it was a very large filling, regardless of type, i would avoid chewing very hard gum balls. In brief: That depends.