The requirement for relining occurs when bone and tissues change due to shrinkage. Possible causes may be:
Post immediate dentures
Bone loss in the upper or lower jaw
Sickness or disease
The bite position, existing teeth and acrylic base(s) must be in good condition and not worn or stained to provide a reline procedure. An impression of your oral tissue is taken inside your denture(s) to provide a working model. New acrylic base material is added to your denture to produce a correct fit. The appearance of your dentures will not change.
Denturists in most cases have no way of trying the denture(s). The procedure is similar to relining. The difference being is that, a rebase replaces all the pink-acrylic denture base material. The existing teeth remain in the exact same place.
Reasons for rebase procedure:
Weakened or old pink denture base