A new denture will not last you forever, and if your old ones are much over 7 years old, your mouth and face will have changed in ways which will make it difficult, or sometimes even impossible for your dentist to build you satisfactory new ones!
The following discussion focuses on the unfortunate effects of keeping an old denture for too long.
1. You may remember that your first denture fit fairly tightly after it was first made, and improved your facial appearance by improving your smile. For many of you, however, over the course of a number of years, the dentures slowly disappeared under your lip, and your upper and lower dentures began to fit together differently bringing your lower jaw forward, and in some cases making it possible to bite only on the front denture teeth.
This happens because the bone that used to support the dentures is slowly reabsorbed by the body allowing the top denture to sit higher and higher under the top lip, and the lower to to drift ever lower below the bottom lip reducing the distance between the nose and the tip of the chin. If you allow this condition to persist for too long, the shape of the face actually changes to accommodate the new conditions. Thin lines begin to develop at the corner of your mouth and your lips appear thinner than normal due to a lessening in the vertical height.
The muscles that allow you to chew shorten permanently, and even if the dentist tries hard to build new dentures that restore the length of your face, and the shape of your mouth, it is possible that you will not be able to tolerate them without constantly clenching on them causing headaches and constant sore spots. If, on the other hand, you get new dentures every 5 to 7 years (as we recommend), your dentist can usually restore the length of your face and the shape of your mouth because the new dentures will be only a little "larger" than the old ones.
2. As the bone that supports the dentures changes shape, more and more space forms between the base of the denture and the gums that it rests on. This is why your old denture begins to get looser and looser. If you simply wear thick denture adhesives, the denture may retain reasonably (they have RETENTION ), but denture adhesives do not support the denture well and it moves around when chewing (and even talking) and dislodges easily, especially when eating. In other words they do not lend the denture STABILITY.
If you wear lose dentures long enough, even with adhesives, your body will tend slowly to build more and more soft flabby gum tissue to fill the spaces between the denture base and the underlying bone. Eventually, you might even get to the point where the space between the bone and the denture is completely filled with this flabby tissue, and you no longer need adhesives to retain the denture. This may seem like a good thing, but the denture moves around on all that flabby tissue. Even if a dentist makes you a new denture, the flabby tissue that now covers the bone will cause the new denture to lack stability as well, and you may be disappointed in the result, with a new denture that dislodges as easily as the old one. If this has become a major problem, the soft tissue can be surgically removed and the ridge of bone surgically altered to create better supporting structures. This is frequently money very well spent, so if your dentist recommends it, give it careful consideration.
On the other hand, you can avoid the problem of flabby tissue altogether by having your dentures relined every two years. This procedure keeps the denture well adapted to the bony ridge and does not give the body enough time to build the redundant tissue in the spaces between the bone and the denture base.
If you have been wearing the same denture for a long time (over 7 years) without routine maintenance, you cannot always expect the dentist to restore your original smile. The reason for this is that during the time you have been wearing the denture, your body has been adjusting to the slow changes that both the denture and your mouth have been undergoing over the years. The ridges (gums) have shrunk back, the denture has worn, and the way you bite has changed, sometimes drastically. As the dentures slowly retreat behind your lips, you are forced to stick out your lower jaw more and more over the years to allow the back teeth to make contact. During this period, the muscles that work the jaws tend to change permanently to accommodate the new way of biting that the old denture has forced upon the jaws. A change in muscle length and bulk may make it impossible for a dentist to fabricate new dentures with the wider smile or longer teeth you had hoped to get from a new denture.
. Lower dentures can be very hard to wear. Many people with upper and lower dentures often wear only the upper on a routine basis, since uppers are retained with at least a degree of suction. Lower dentures are the real challenge, since they are
retained mostly by the muscles of the lips and cheeks, and the tongue. Fortunately, now there is a new, relatively inexpensive way to stabilize the lower denture. Indeed, this technology can make the denture act almost like real teeth.