If your lower denture moves when you eat or talk while the upper one stays put, you are not doing anything wrong. The upper denture seals against the roof of the mouth across a broad surface. The lower one has to sit on a narrow ridge with the tongue underneath it. There is simply far less to hold on to.
Why the Fit Changes Over Time
The main reason is resorption. Natural tooth roots stimulate the jawbone every time you chew. Once the roots are gone, the body gradually reclaims bone it no longer has a use for. The ridge your denture was fitted to slowly flattens, and a denture that fit beautifully three years ago now rocks.
Two other causes come up regularly. Warping, usually from hot water or a drop onto a hard floor. And dentures that were never well fitted to begin with, which is a common outcome with mail order or bargain prosthetics.
If your denture is brand new and feels unstable, give it a few weeks. Learning to control a new denture takes practice and most people settle in.
The Four Real Fixes
- A reline. We add material to the base so it matches the ridge you have now rather than the one you had when it was made. This is the least involved option and often the right one.
- Adhesive. Reasonable as a bridge while you decide, but it is managing a symptom. If you need increasing amounts of it, the fit is the problem.
- A new denture. Sensible if yours is damaged, poorly made, or more than about five years old.
- Implant retained dentures. Two to four implants in the lower jaw give the denture something to lock onto. It stays put when you eat, and the implants slow the bone loss that caused the problem to begin with.
Which One Is Right for You
That depends on how much bone you have left, how old the denture is, and what you want out of it. Someone whose denture is four years old and rocking slightly is usually well served by a reline. Someone who has been layering on adhesive for two years to get through dinner is usually happier with implants.
We will tell you honestly which one applies. Our dentures and partials page covers the options and costs, and dental implants explains the implant retained route.
A slipping denture is worth fixing. People quietly stop eating foods they like and start avoiding conversation, and it happens gradually enough that they do not notice how much they have given up.