When teeth have been extracted, the body will slowly resorb the bone that once held the teeth. When dentures are made, a mold is made of the mouth and then the denture is constructed. But as the years go by, the bone continues to erode away while the plastic stays the same. This causes gaps to form between the dentures and the gums, which will eventually cause the dentures to become loose and ill-fitting. The good news is that the plastic can be relined without having to make an entirely new denture.
To reline a denture, the dentist will hollow out the inside of the denture without affecting the teeth. An adhesive is painted on and the inside of the denture is filled with an impression paste. This is inserted into the mouth and it sets, thus making a mold of the new form of the gums. A lab tech then makes a model by pouring plaster into the mold. He then cuts aways the old plastic and packs new plastic between the new model and the denture teeth. Voila – a well-fitting denture, almost good as new. This procedure can be done much more inexpensively than constructing new dentures. It can help restore a denture to its original fit.