Denture adhesive: when does it help, and when is it a warning sign?

A full denture does not stay in by being stuck to the gum but by fitting the ridge it sits on: the thin layer of saliva in between and, in the upper jaw, the suction created under the palate hold the denture in place. Adhesive is an aid added to this mechanism. When it comes into contact with saliva it swells, fills the very small gaps between the denture and the gum and forms a sticky layer. The result is a firmer hold and less food getting under the denture.

That is why adhesive works best in a mouth where the denture already fits well. At a busy dinner table, during a long conversation or for someone who is just getting used to their denture, a small amount can noticeably boost confidence. A dry mouth also reduces how well a denture holds; in someone with less saliva, adhesive can support the hold, but the cause of the dryness should be investigated separately.

What adhesive cannot do is make a denture that does not fit sit properly. When the gap between the denture and the gum grows, people start applying adhesive thickly enough to fill that gap. A thick layer lifts the denture up from where it should be, changes the way the teeth meet and concentrates the pressure on a few spots. The denture feels as if it is holding, but the rubbing and pressure underneath carry on.

The reason the need for adhesive grows over time is usually not the denture itself but the base underneath it. After tooth loss, the jawbone slowly shrinks over the years; the ridge gets lower while the denture stays the same, and the gap between them grows. The sequence patients describe is almost always the same: at first no adhesive is needed, then it is used only on special occasions, then every morning, and in the end several times a day and more each time. Every step of this sequence tells you the fit needs checking.

Some adhesive creams contain zinc. Used as directed and in moderation, these are considered safe. The problem is use over many years, far beyond what is recommended: cream that squeezes out is swallowed, and an excess of zinc can build up in the body. The medical literature has reported cases of nerve damage, with numbness and tingling in the hands and feet, linked to this kind of long-term overuse. If you use adhesive every day, checking the ingredients on the packaging and choosing a zinc-free product is a sensible precaution.

Cleaning is also part of using adhesive. Residue left on the gums and palate creates a surface for bacteria and fungi to cling to, and can cause bad breath and irritation. Adhesive should be cleaned completely off both the denture and your mouth every evening, and the denture should be taken out at night.

The same product means two different things in two different mouths. What decides it is how the denture holds without adhesive.

The product's own instructions always come first. The sequence below is a general guide; the differences between cream, powder and pad types are written into the steps.

1. 1

   Clean the denture

   Remove all of the adhesive left from the day before and brush the denture. Applying a new layer over the old one lifts the denture and leads to residue building up. With creams, most products recommend drying the denture first; with powders, leaving it damp.

2. 2

   Start with a small amount

   For cream, put three or four pea-sized dots on the surface of each denture that faces the gum, and do not put them too close to the edges. For powder, sprinkle a thin, even layer and shake off the excess. For pads, cut the pad to the shape of the denture and moisten it as the instructions say.

3. 3

   Put the denture in place

   Rinse your mouth with water, put the denture in and hold it for a few seconds by pressing gently or slowly closing your teeth together. Wait for the time the product recommends before eating or drinking.

4. 4

   Check whether any has squeezed out

   If adhesive is oozing from the edge of the denture into your mouth, you have used too much. Use less next time; adhesive that squeezes out is swallowed and adds nothing to the hold.

5. 5

   Notice how many times a day you apply it

   Adhesive applied in the right amount is usually enough for a good part of the day. If you have to take your denture out and apply more again and again during the day, the problem may be the fit, not the amount.

6. 6

   Clean it off completely in the evening

   Take the denture out and clean the adhesive off it with a soft brush under lukewarm running water; do not use hot water. Rinse your mouth with lukewarm water and gently wipe away what is left on your gums and palate with a damp piece of gauze or a soft brush. Keep the denture in water or a cleaning solution overnight.

7. 7

   Note how long a tube lasts

   Write the day you start a new tube and the day you finish it on a calendar. If a tube of the same size runs out noticeably sooner than before, you have been using more without realising.

If you need more and more adhesive, the next step is not to try another product but to look at the fit of the denture. The options below start with the least invasive.

Adhesive used according to its instructions is considered safe. The problems below mostly come from using too much, not cleaning it off properly or relying on adhesive to hold a denture that does not fit.

Once the fit has been corrected, the need for adhesive usually drops noticeably. The course below is the usual sequence when you go to your dentist with a denture that needs more and more adhesive.

1. The day of the examination

   Bring your denture with you and, if possible, come without adhesive that day; your dentist needs to see how the denture holds on its own. Explain how often and how much adhesive you use, and how long a tube lasts.

2. The first few days after an adjustment or relining

   Try the denture without adhesive first; most people feel the difference in the first few days. Because the new layer can change where the pressure falls, a small adjustment may be needed.

3. The first month

   If you still need adhesive every day, and in increasing amounts, say so at your check-up. If the bony ridge has become very low, the effect of relining may not last long; in that case a new denture or support from implants is discussed.

4. The long term

   Go for regular check-ups even if your denture is new; the fit changes slowly, so it is hard for you to notice. Keep tracking your tubes: an increase that starts again tells you when your next check-up is due.

Adhesive itself is not a treatment. These are the items that determine the scope of the procedures that come up when the need for it grows:

The age and condition of the denture

With a denture whose teeth and base are sound, an adjustment or relining may be enough; a worn or cracked denture is replaced.

The type of relining

Relining can be done in the dental chair on the same day or in the laboratory; the method also determines how long the denture will be out of your mouth.

The condition of the bony ridge

If the ridge is still well defined, steps involving the denture remain useful for a long time; if it has flattened, support from implants comes up.

The type of implant support

A removable denture that sits on a few implants and fixed teeth screwed onto implants are plans of different scope.