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11 Oct 2022

Loose Dentures

Are your Dentures Loose and Uncomfortable? 

Woman Rejecting Her Dentures by Dr Dean Lloyd

There are many reasons why a denture can be loose. One reason may be because the base does not fit tightly against the gums, which is what most people think is the problem, however, a more accurate reason, and one less obvious, is in the design of the pink denture base plate itself.

Lower Dentures:

For example, if the inner flanges of your lower denture are too long, (see fig 1.) no matter how tight your lower denture fits over your gum, it will still be loose.  


Here’s why. As you speak and eat, the floor of your mouth (the skin on each side of your tongue) moves up and down. This constant rising and dropping of the floor tissue push and release against the long flanges of your denture. As the floor bobs up and down, so does your denture, causing it to be loose.

Your dentist may even make the situation worse.

Sometimes practitioners reline loose lower dentures thinking that the tighter fit will solve the patient's problem, however, if they don't reduce the flange length before they take the impression, the flange length will increase and thereby exacerbate the problem!

To summarize, the longer the inner flange of your lower denture, the looser your denture may be.

Long Lingual Flange on Lower Denture by Dr Dean Lloyd

Fig. 1

This image shows an over-extended inner flange on a lower denture.

Upper Denture:

When people gag on their upper denture, they think it’s because their denture is too long toward the back of their throat. When they talk to their local dental practitioner, he or she may shorten the denture plate at the back. This action, in some cases, may worsen the situation.


Let me explain. When your GP puts a wooden paddle onto the back of your tongue - you gag, "right?" So, when it comes to your denture, you also gag because the denture is loose, and it is dropping down onto the back of your tongue.


Just like the wooden stick touching your tongue makes you gag, so does a denture touching the same area of your tongue.

Rear Seal of Upper Denture Too Short by Dr Dean Lloyd

Fig. 2

This image shows an upper denture with a rear seal that has been trimmed too short.

So, if the rear seal is too short (see fig. 2) the denture may be loose and drop down as you speak or eat. This means that, in some cases, rather than shorten the upper denture’s pink base, your practitioner may need to lengthen it. By lengthening the palate at the back, your denture may not drop down. In other words, once your denture fits snugly against your palate it may no longer be loose and thereby not cause an unpleasant gagging reaction (Here your practitioner will have to make the decision to either shorten or lengthen your denture’s rear seal.)

As a side note: Never shorten your denture's palate at home. Let your practitioner assess the situation and then if they make the wrong choice, to either lengthen or shorten the rear seal, you may not be responsible for the bill!

Upper Denture's Outer Flange:

Your upper denture is also held in place by its outer flange. (See yellow line in Fig. 3). 

If your upper denture leaves you with either a sunken or bloated-looking face when inserted, this may indicate that the outer flange is either inadequate or over-extended. 

  • If your denture is over-extended in this area, your denture may “pop” loose due to the unnecessary extra pressure caused by a tight or bloated lip.

  • If your denture’s flange is inadequate, your denture may “slide” down because of insufficient lip support.

The contour of your upper denture’s flange must be checked “by you” in the wax try-in stage when getting new dentures. It can also be corrected when you get a reline done on your existing upper denture.  

Upper Denture Showing  Lip-line by Dr Dean Lloyd

Fig. 3

This image shows an upper denture with the outer flange and the patient's lip line marked in yellow. 

These, of course, are only some of the reasons why your dentures may be loose.

Author: Dr Dean Lloyd

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