dealing with Dentures..

Having an operation next week to remove the implants in my jaw.I lost all my real teeth years ago owing to the illness I have.To be honest I think its going to be a disaster because when the illness flares in the mouth the gums turn also semi solid but they say its the only option left is me having Dentures.

Just wondering about how long does it take getting used to them? I noticed those ad's for Denture seals etc? do any of them really work and help keep them in place?

Thanks