Soft Denture Liners

By Brian J. Gray, DDS, MAGD, FICOI

A soft liner is placed in that part of a denture base that contacts tissues. This provides comfort for those persons experiencing considerable pain while wearing a denture that has a hard plastic interface (the inside of the denture).

These individuals may have a low threshold for pain, and/or the gum tissue that overlays jawbone is usually thinner than normal and does not resist pressure well. When such tissue is compressed between hard jawbone and hard denture plastic, pain is easily elicited. Replacing one of these hard interfaces with a soft denture liner helps eliminate or reduce this painful tissue compression.

Some Characteristics of Soft Denture Liners

• Denture liners are usually fabricated from special medical grade rubber or silicone-type compounds. The silicone materials are generally more compressible and, consequently, softer.
• In order for these materials to function adequately, they must be reasonably thick. Therefore, the amount of plastic that needs to be removed from the inside of a denture to allow room for these liners may weaken some dentures. In those cases, it becomes necessary to incorporate a reinforcing metal framework within the body of certain dentures. There are several steps involved in installing a soft liner, such as impressions and various laboratory procedures.
• Soft denture liners tend to continually harden, though a patient may not be aware of this happening because the process is gradual. However, they eventually will begin to have increasing problems until a new soft liner is placed.
• Denture liners are porous in nature, which accounts for why they are soft. However, this porosity contributes to their deterioration and collection of microorganisms.
• If a soft denture liner becomes contaminated with disease-causing microorganisms (a fungus for example), it may not be possible to decontaminate the denture without having to replace the liner.
• Persons with dry mouth usually have difficulty wearing dentures due to pain and irritation caused by the hard denture surface rubbing against underlying tissues that are not lubricated with adequate saliva. While soft denture liners would appear to be ideal for such individuals, they are generally much more difficult to maintain. Because impaired saliva production allows a very significant collection of microorganisms to buildup in the mouth, this usually results in unacceptable contamination of porous soft denture liners unless meticulous hygiene is maintained.
• While denture liners generally will last longer than a year, they should be replaced on an annual basis or sooner. The frequency of replacement depends on each situation and the patient's oral hygiene.

Advantages of Soft Denture Liners

• A gentle and kinder denture interface for those individuals with sensitive underlying tissues.
• The soft denture liner tends to compress and conform to a constantly changing jawbone surface. While this helps prevent pain from a moderately unbalanced bite resulting from jawbone shrinkage, it is not a long-term substitute for regular adjustments to balance a denture bite.

Disadvantages of Soft Denture Liners

• Soft denture liners continually deteriorate and collect microorganisms easily; therefore, they generally are replaced on an annual basis.
• Because soft denture liners help reduce pain from an uneven bite, patients may get a false sense of security, thinking their denture is adequately functioning while the bite continues to deteriorate. Routine dental check-ups are a necessity.
• Generally, soft tissue liners are more expensive than a conventional hard denture liner.