Your dentures fit well when you first got them. Now the lower one lifts when you talk, and food gets under the upper one. The adhesive you once used now and then has become a daily habit. If you are asking why dentures get loose when nothing about them has changed, look underneath them. The bone your denture sits on has been shrinking since your teeth came out, and the denture cannot shrink with it.
Why do dentures get loose when they fit at first?
A denture is made of rigid material, shaped to match your gums on the day it was made. It cannot shrink or stretch afterward, but your jaw is living bone and keeps changing.
While you have teeth, every bite pushes each tooth slightly into its socket. That pressure travels through the root into the bone around it, and the bone stays because it is being used. When a tooth comes out, that load disappears. The body then removes bone it no longer needs, much as a muscle in a cast gets smaller. A denture presses on the surface of the gum, which does not load the bone from the inside the way a root did.
So the ridge, the curved strip of gum and bone a denture sits on, gets lower and narrower. The denture stays the size it was. A gap opens between them, the denture starts to rock, and the seal that held the upper one in place begins to leak air.
How fast does the bone under a denture shrink?
Fastest at the start, and then more slowly for years afterward.
A Danish study measured 46 people for 12 months after a back tooth was removed. The major changes to the site happened within that first year (Schropp et al., 2003). That is why the fit of a first denture can change quickly.
The loss does not end after that year. A classic study followed complete denture wearers for up to 25 years, and their ridges kept shrinking through the whole period (Tallgren, 1972).
The shrinking costs a lower denture more, because of how each one stays in. An upper denture covers the roof of the mouth, which gives it a wide surface to hold onto. A lower one sits on a narrow strip of ridge, with the tongue and cheeks moving around it all day. As that strip shrinks, a lower denture has very little left to grip.
Bone is not the only thing that changes. An upper denture also relies on a thin film of saliva between its base and the roof of your mouth. Many common medications reduce saliva, according to the National Institute of Dental and Craniofacial Research, and a drier mouth weakens that hold. Our post on dry mouth and medications explains why saliva drops.
What happens if you keep wearing a loose denture?
A loose denture moves when you chew, and the movement is where the trouble starts.
Each time it rocks, it presses hard on a few small spots instead of spreading the load across the ridge. Those spots get sore, and a sore spot makes people chew on the other side or avoid firm food. Food and plaque collect in the gap underneath, which irritates the gum further.
Adhesive can hide the gap for a while. It fills the space between the denture and the gum, so the denture feels steady again. It does not change the shape of either one, and the gap usually keeps growing under it. Needing more adhesive each month is itself a sign that the fit has changed.
Which fix actually works for a loose denture?
There are three fixes, and they solve different problems.
Does a reline fix a loose denture for good?
A reline adds a new layer of material to the side of the denture that touches your gums, shaped to your ridge today. The teeth and the bite stay the same, and the fit comes back.
What a reline cannot do is change the bone. The ridge keeps shrinking under the new layer, so a relined denture can loosen again later.
When is a new denture the better fix?
When the teeth on the denture have worn flat, the base has cracked, or the bite has shifted, a reline is no longer enough. A new denture starts over: new impressions, a new base and new teeth. Front Royal Dental Group offers both full and partial dentures.
A new denture fits better on day one. It still sits on the same ridge, though, and that ridge will keep changing.
Do implants stop the bone under a denture from shrinking?
They slow it, and they are the only one of the three fixes that changes what happens to the bone. A dental implant is a small titanium post placed in the jaw where a root used to be. When you bite, the force goes through the implant into the bone again, which is the load the bone lost when the teeth came out.
In one five-year study of the lower jaw, the back of the ridge lost an average of 1.63 mm of height under conventional dentures. Under dentures held by two implants, it lost 0.69 mm (Kordatzis et al., 2003). The implant group lost less than half as much height as the denture group, but it still lost some.
Implants also change how the denture stays in place. An implant-supported denture attaches to the implants, so it no longer depends on suction or adhesive to stay put. A fixed All-on-4 or All-on-X full-arch is the other implant route, with teeth that stay in rather than coming out at home. Ask which design is being proposed for you, and whether it comes out for cleaning.
Implants mean surgery, a healing period of several months and a higher cost than a denture alone. Whether they work for you depends on how much bone is left and on your health history. A 3D scan of your jaw shows the bone before anyone recommends them, and we use guided implant surgery to plan placement from that scan. One honest note: we do not offer sedation of any kind. Treatment here uses local anesthetic, and you can ask to pause at any time.
How do you know which fix your denture needs?
The answer comes from looking at your mouth, not from how long you have had the denture.
At an exam, a dentist sees how the denture sits on your ridge, where it rocks and whether the teeth on it have worn down. If implants are on the table, a 3D scan shows how much bone there is to work with. After the exam, you get a written estimate before treatment starts. If you want to compare the types of denture first, our post on denture options walks through them.
What to do
If your denture has started to rock, rub or need more adhesive, bring it to an exam and ask what has changed underneath it. The exam tells you whether a reline, a new denture or implants fits your mouth, and you decide what happens next.
Ready to get started? Schedule a visit with Front Royal Dental Group, or call (540) 636-2003.
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