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.
Grooves in your teeth should not cause sensitivity to chewing hard foods. I know 6 months seems like a long time but some teeth take a very long time to quit being sensitive after a filling. It is too bad that you had all four molars done at once and that all four of them got sensitive.