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.
Hollowing out of the inside of 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.
In the first part of this blog, I talked about why not to use denture adhesives. Once all the reline procedures have been tried, there are occasional instances where there is still not enough bone to provide enough surface area for adequate retention and stability. In those cases, a patient will usually have to rely on denture adhesives. Also on cases where a patient would be too self-conscious about a denture slipping while out in public, denture adhesives can be helpful. Denture adhesives come in powder, paste, or adhesive pads. Any of the forms work reasonably well, so which variety or brand is totally up to personal preference. There has been a lot of talk lately in the media about zinc in denture adhesives. Too much zinc in the body can cause nerve damage. It turns out that patients who were experiencing symptoms of zinc toxicity were overusing the product. Only the smallest amount of denture adhesive should be used and that should minimize any toxic effects. Lately, many companies have reformulated their products to be zinc-free, so that would alleviate any concerns.
Denture adhesives are used to help retain dentures in the mouth. Before denture adhesives are used, a dentist should be consulted. Ill fitting dentures can cause areas of chronic irritation which can lead to mouth sores and ulcers and eventually could be a source of malignant transformation. Mouth cancer is not something to be taken lightly, so a dental examination is always best to have before considering denture adhesives. Most ill-fitting dentures can be relined with new plastic to have them conform to the gums better. When teeth are removed, the body realizes that there is no need for the bone to hold the teeth in, so it slowly allows the bone to dissolve. Since the denture plastic doesn’t change, gaps begin to form which causes a loss of suction. A reline will fill in the gaps, restoring the suction. There are other times, especially on the lower, where there is not enough bone for adequate retention and stability. In this case, it is best to train the muscles to keep the denture in place while chewing and talking. This will allow the denture to stay in place during function.
A good fitting denture along with an adequate amount of saliva will usually allow a denture to fit well without the use of denture adhesives. However, over time, the gums will naturally shrink and thus the dentures will begin to loosen. The better thing to do is to go to your dentist for a reline. An impression is made of the new gums and new plastic is processed into place giving the denture a fit that is as good as new. In the interim, denture adhesive can be used, but it should not be relied on as ill-fitting dentures can be a source of chronic irritation that could possibly lead to malignancy. Another reason that denture adhesive may be needed is very flat gum ridges. If there is not enough bone present to resist the lateral forces of chewing, the denture could become continually dislodged.
Powder and Paste Adhesives
There are a number of varieties of denture adhesives, mostly pastes, powders, and wafers. All types seem to work reasonably well, although pastes should only be used sparingly because they tend to be very thick in viscosity and could throw off the proper fit of the denture.
Over the years, dentures will become looser and looser. This is not because the denture is changing but because the gums are shrinking. Alveolar bone (the bone that holds the teeth in) is very labile bone. That means that it is constantly changing to meet the current conditions. This is an important property due to the constant changes in the forces while chewing with natural teeth. However, the sole purpose of alveolar bone is to hold the teeth in, so once a tooth is removed, it thinks that its job is done and begins to resorb. When the teeth are first lost, there is usually a fair amount of bone left behind, unless there was severe periodontal (gum) disease present. However, as time goes on, the bone will continue to erode until eventually, there will not be much left. Since the bone shrinks, dentures must be periodically relined.
Impression material inside denture
To reline a denture, impression material is placed into the actual denture to make a mold of the changed gums. A technician will then grind out the old plastic and process new plastic to perfectly match the present situation. This is a much less expensive way to make an old set of dentures fit as good as new, and avoids the great expense of an entirely new set.