I had dentures for 15 years without a problem, and since I got these new ones, they are loose and I cannot chew!
How often do you think we asked why is my new denture loose?.. A lot!
There are a number of reasons why new dentures are worse than old dentures. Some are technical dental problems that can be fixed, and some are patient problems that cannot be fixed.
The first is adaptation.
The mouth changes over time. It changes slowly, and your brain is easily able to adapt to these changes since they are occurring so slowly that you don't notice. The gums and bone are shrinking slowly. The teeth are wearing. The distance from your chin to your nose is reducing as the gums and teeth get shorter so you have to close your mouth further to get your teeth to touch (this is why really worn dentures make you look older because they make your scrunch your face up to get your teeth to touch).
When we make new dentures, we correct all these problems all at once. It is not uncommon for the height of the gums and the teeth to reduce by up to half a centimetre with old dentures. This means that the patient new dentures need to be 5 – 6mm bigger to compensate.
Imagine how big a change this is for the automatic program in your brain that controls chewing to deal with. We know that everyone's chewing function reduces for up to six weeks with new dentures no matter how good they are.
Your tongue and lips and cheeks are also very important to holding your denture in position, so a lot of time is taken for your brain to reprogram to get used to the new shape of the denture. Like riding a bicycle.
The second problem is expectations.
Often your old denture is also loose, but you think it is just because the denture is old. Surely if it fits like a new one, it will be stable. Nope. Often looseness is due to the shape of the mouth, and a new denture may not fix this problem
The third problem is the way the gums shrink.
Around the lower jaw, there are lot of muscles. The lip, tongue and cheeks are all muscles that move a lot. When the teeth are just extracted, the jaw is very big and pokes a long way above the muscles so it is very stable. As the jaw shrinks down lower, the top of the jaw is closer to the muscles and the movement of these muscles is more likely to bump the denture. This is a problem that cannot be fixed with new dentures and no matter how many adjustments you get, the denture will still pop up when you chew, laugh or speak.
The fourth problem is a design issue.
The part of the denture that pokes down either side of the jaw is called the flange. On the lower, when you take the mould of the patient's mouth, their tongue is sitting down. However, as soon as they speak, the tongue lifts up. If the flange of the denture pokes down too far, the tongue will press on it and lift the denture out as you speak or eat. This is the most common problem that we find. In this case, the flanges need to be trimmed back so that the tongue cannot lift them.
Lastly, the bite.
If the teeth do not all hit at the same time with a solid thunk, then the denture will tilt. Having some teeth hit harder than others is a big problem and will cause pain, and dentures that move about all the time. The bite is not easy to check as the pressure of the bite will make them tilt and then hit together more evenly
If the bite and the flanges are correct, and after a period of time, you still cannot get used to the dentures, it means your brain is not wanting to reprogram to the new dentures, or the shape of the mouth does not allow you to have stable dentures.
We often get people with new dentures and most of the time it is flanges or bites that are the problem, but some of them need implants to get any comfort.