A. This is the main disadvantage of immediate dentures. the lab technician who makes thed dentures- ready to be fitted immediately after the tooth/teeth ahve been taken out, has to guess where the teeth are going to sit. the fit of the dentures isnt always perfect and the surrounding gums shrink away after a while, so that the denture become loose. You may need to have the denture relined- or once the gums have settled, have a new, better fitting conventional denture.