A lower denture that slips, rocks, or comes loose while eating or speaking is a common problem. Lower dentures are generally harder to keep stable than upper dentures because the lower jaw has a smaller supporting surface and the tongue, cheeks, and lips can move the appliance during normal activities. The American College of Prosthodontists (ACP)
Several factors can cause a lower denture to stop fitting properly.
After natural teeth are lost, the bone supporting them gradually changes. As the underlying ridge shrinks or changes shape, the original denture may no longer closely match the tissues underneath it.
This can reduce:
The ACP explains that changes in the hard and soft tissues beneath dentures can eventually lead to loss of fit and retention.
The tongue is another major reason lower dentures can move.
During eating, swallowing, speaking, and other everyday movements, the tongue can contact the denture and shift it.
This makes achieving the same level of stability as an upper denture more challenging.
Dentures are not designed to last indefinitely.
The denture base and artificial teeth can wear down, while changes in the mouth can gradually make the appliance less suitable.
The ACP recommends professional evaluation when a denture has been in use for more than five years or when it becomes unstable, damaged, uncomfortable, or difficult to use.
Changes in the relationship between the upper and lower teeth can affect how forces are distributed when chewing.
A dentist can examine the bite and determine whether adjustments are appropriate.
Changes in oral tissues can alter how a denture contacts the gums.
Even when a denture originally fit well, changes over time can affect retention.
A loose lower denture should generally be examined rather than repeatedly modified at home.
A dentist or prosthodontist can evaluate:
The American Dental Association (ADA) notes that poorly fitting dentures may need to be relined or replaced rather than relying on adhesive to compensate for the poor fit.
One of the first solutions a dentist may consider is a denture reline.
A reline modifies the tissue-contacting surface of the denture so that it better matches the current shape of the mouth.
This can be useful when:
A reline does not solve every denture problem. If the denture is significantly worn, damaged, poorly designed, or otherwise unsuitable, replacement may be more appropriate.
Sometimes the most appropriate solution is a new denture.
Replacement may be considered when:
The ACP identifies instability, loss of retention, inability to eat, damage, and chronic irritation among reasons a removable denture may need professional evaluation for replacement.
Denture adhesive can provide additional retention for some people.
Adhesives are available as:
The ADA notes that adhesives can improve retention and chewing performance when used appropriately. However, an adhesive is not considered a definitive solution for an ill-fitting denture.
If a lower denture constantly requires large amounts of adhesive to stay in place, that may be a sign that the underlying fit needs to be evaluated.
The FDA similarly states that properly fitted and maintained dentures generally should not require adhesive and that loosening caused by changes in the jaw can require relining or replacement.
When adhesive is recommended, it should be used according to the manufacturer's directions.
General considerations include:
Some denture adhesives contain zinc. Excessive use of zinc-containing adhesives has been associated with potential health problems, which is why the FDA recommends following product instructions and avoiding excessive use.
For people whose conventional lower dentures remain unstable despite appropriate adjustment or replacement, dentists may discuss implant-retained overdentures.
Dental implants are placed into the jawbone and can provide attachment points for a removable denture.
The denture can then connect to the implants rather than relying entirely on the gums and surrounding tissues for stability.
The ACP specifically states that implants can stabilize and retain a lower denture, potentially improving chewing efficiency and reducing movement.
An implant-retained overdenture is still removable, but it attaches to dental implants.
Depending on the treatment design, attachment components allow the denture to connect to the implants and remain more securely positioned.
The patient can generally remove the prosthesis for cleaning.
The ACP explains that implants can provide retention and support for removable overdentures, allowing the denture to snap onto the implants and reducing dependence on adhesive.
| Feature | Conventional Lower Denture | Implant-Retained Overdenture |
|---|---|---|
| Support | Gums and oral tissues | Implants plus oral tissues |
| Removable | Yes | Usually yes |
| Adhesive | May be useful | Often less necessary |
| Stability | Can be limited | Generally provides additional retention |
| Surgery | No | Requires implant placement |
| Maintenance | Denture care and dental visits | Denture plus implant maintenance |
| Suitability | Depends on oral anatomy and fit | Depends on bone, health, anatomy, and treatment assessment |
Implant treatment is not automatically the right choice for everyone. A dental professional needs to evaluate bone availability, oral health, medical considerations, treatment goals, and the condition of the existing denture.
In some cases, an existing denture may potentially be adapted to work with implants.
However, it is not simply a matter of turning an ordinary denture into an implant.
The ACP notes that implants can sometimes be placed beneath an existing denture when the denture is otherwise in excellent condition, but the appliance must first be carefully evaluated.
A dentist or prosthodontist can determine whether the existing appliance is suitable or whether a new overdenture would be preferable.