An immediate denture is designed to be placed in the mouth immediately after the extraction of your natural teeth. An immediate denture eliminates the embarrassment of having to go without teeth, while the gums are healing.
An immediate denture is designed to fit your mouth at the time impressions are taken; however, after a few months your gums will change drastically due to "gum resorption." It's possible that the denture will rub against the gums when it is first placed, which may be very sore until it can be adjusted. Gums shrink the most within the first year of having teeth extracted. Most patients will require relines within a few months, to restore the fit of their dentures. Expect that the first year of wearing dentures will also be the most difficult and costly.
Since an immediate denture covers over the surgical site and the tooth sockets, it helps keep that tender surgical area from becoming irritated, much as a bandage would. Do not remove your denture by yourself, even for just a few minutes, until your dentist tells you it's all right. The gum tissue underneath the denture has a tendency to swell. If you take the denture out for very long, you may never get it back in again.