Dentures are removable prosthetic devices, typically made from acrylic resin, designed to replace missing teeth and surrounding tissues. Since these appliances spend most of their time in the moist environment of the mouth, they must be kept moist when not being worn. The answer to whether dentures should be kept in water overnight is definitively yes. This practice is fundamental for maintaining the physical integrity of the device and the health of the wearer’s mouth.
Why Dentures Need to Stay Wet
The physical structure of modern dentures relies on acrylic resin (polymethyl methacrylate or PMMA). This porous material absorbs moisture to maintain its shape and flexibility. When dentures are removed from the mouth, exposure to saliva stops, and the material begins to dry out.
Allowing the denture to dry out overnight causes the material to dehydrate and shrink, leading to warping and distortion of the precise fit. This change can disrupt the comfort and stability of the appliance. A persistent lack of moisture also causes the acrylic to become brittle, increasing the risk of cracking or breaking.
Choosing the Right Soaking Solution
While soaking in plain water prevents the acrylic from drying out, water alone is not sufficient for proper hygiene and cleaning. Dentures accumulate a complex layer of microorganisms, known as biofilm, composed of plaque, bacteria, and fungi like Candida albicans. This biofilm colonizes microscopic pores in the acrylic surface, leading to odor, inflammation (denture stomatitis), and other infections.
The mechanical action of brushing removes loose debris and some plaque, but soaking provides a chemical deep clean. Specialized commercial denture cleansers often come as effervescent tablets containing alkaline peroxide. These solutions create a chemical reaction when dissolved in water, working to break down the organic matrix of the biofilm and kill the embedded microorganisms. For optimal care, the denture should always be thoroughly brushed with a dedicated denture brush and a non-abrasive cleanser before being placed into the soaking solution.
Substances That Damage Dentures
Denture materials are softer and more delicate than natural tooth enamel, so certain common cleaning agents can cause permanent damage. Using regular toothpaste is discouraged because it contains abrasive polishing agents, such as silica or alumina, designed to scrub natural teeth. These abrasives create micro-scratches on the softer acrylic surface, providing new areas for bacteria and stains to lodge.
Exposure to high temperatures, such as boiling water, is destructive to the denture’s structure. Since acrylic resin is a thermoplastic material, heat causes the polymer structure to relax and distort immediately, resulting in irreversible warping and a complete loss of fit. Household cleaners like bleach (sodium hypochlorite) should also be avoided, as the harsh chemicals can weaken the acrylic, cause discoloration, and potentially corrode any metal components.