A soft denture reline adds a cushioning layer to the inside surface of an existing denture to improve its fit and comfort against the gums. This adjustment becomes necessary as the shape of the mouth naturally changes due to bone loss or gum tissue shifting, causing the denture to become loose. By restoring intimate contact between the denture base and the oral tissues, a soft reline enhances stability, suction, and the ability to chew comfortably.
Defining the Soft Reline Procedure
A soft reline involves applying a flexible, rubber-like material to the denture surface that rests directly on the gum tissue. Its primary purpose is to provide a shock-absorbing layer, especially for patients with tender gums or recurrent sore spots. This cushiony layer distributes the forces of chewing more evenly across the sensitive tissue.
The materials used are typically long-term soft lining polymers, such as silicone-based products (e.g., dimethyl siloxane) or plasticized acrylics (e.g., PEMA derivatives). This soft material differs from the hard acrylic resin that makes up the main body of the denture. Dentists often use a soft reline as a conditioning measure to allow irritated tissues to heal before a permanent hard reline or new denture is fitted.
Typical Duration and Factors Affecting Longevity
The lifespan of a soft denture reline is temporary, generally lasting between one and two years before replacement is needed. Some long-term liners may last up to three or four years, but this duration is highly variable. The soft material is constantly exposed to the dynamic environment of the mouth, causing it to gradually lose flexibility and harden over time, which is the main reason for failure.
For acrylic-based relines, hardening occurs because plasticizers slowly leach out into the oral fluids. While silicone-based materials are more stable in hardness, they are more prone to bond failure between the soft layer and the hard acrylic base. The constant absorption of water and saliva also contributes to the material’s dimensional instability and hardening.
Patient habits and biological factors substantially affect the material’s breakdown. Acidic saliva, high intake of acidic or alcoholic beverages, and certain denture cleansers accelerate the deterioration of the polymer structure. Thermal cycling from ingesting hot and cold foods also negatively affects the material’s properties. The porous nature of the soft material makes it susceptible to colonization by microorganisms, such as Candida albicans, which compromises the liner’s integrity.
Care Practices to Extend Reline Life
To maximize the functional life of a soft reline, a specific and careful cleaning routine is necessary. Dentures should be rinsed under cool, running water and brushed gently with a soft-bristled brush. Use a mild, non-abrasive cleanser specifically designed for dentures, avoiding regular toothpaste which can scratch the soft material.
Manufacturers advise against soaking soft-lined dentures in effervescent cleansers for extended periods, as this accelerates the hardening process. When not worn, the denture should be kept immersed in water or a recommended soaking solution to prevent the soft liner from drying out. Avoiding excessive heat is also important because high temperatures can damage the soft lining material and potentially warp the denture base.