How to Clean and Care for a Night Guard or Retainer

By Dr. Boris Zusin · Published August 2, 2026

A custom night guard or retainer is a real investment, and keeping it clean isn't just about hygiene — a buildup of bacteria and fungus on the appliance can cause bad odor, gum irritation, cavities, and mouth infections, and it shortens how long the appliance itself lasts. The good news: the routine that actually works — gentle brushing plus an occasional chemical soak — takes less than a minute or two a day.

Every Morning, Right After Wear

Rinse the guard under cool or lukewarm water as soon as you take it out — never hot, which warps the material and permanently changes the fit. Brush it gently with a soft toothbrush and cool water; a small amount of mild liquid hand soap or dish soap works well and is gentle on the material, so there's no need for anything stronger. Rinse it again and let it fully air-dry on a clean surface before putting it away.

Storage

Store the guard in the ventilated (vented) case it came in, kept dry when it's not soaking — never wrapped in a napkin or tissue (a surprisingly common way these get thrown out by accident) and never loose in a bag or pocket. Keep it away from heat entirely: no hot cars, dishwashers, boiling water, or direct sunlight. It's also worth keeping the guard out of reach of pets — dogs in particular are drawn to the smell and will chew right through one.

Deeper Cleaning, One or Two Times a Week

Soak the guard in a denture or retainer cleanser tablet (Polident or Corega, for example) dissolved in a glass of cool water, following the soak time on the package — usually a short soak rather than an extended one. Rinse thoroughly with water before putting it back in your mouth. If you already own an ultrasonic cleaner (the kind sold for jewelry or dentures), that's also a safe and effective option for this weekly deep clean.

What Not to Use

• Regular or whitening toothpaste for scrubbing — it's abrasive, scratches the surface, and those scratches trap more bacteria than a smooth surface would.
• Hot or boiling water, the dishwasher, or the microwave — unless your dentist has specifically told you microwave cleaning is safe for your particular appliance.
• Bleach or household disinfectants for daily use — these can discolor, weaken, or corrode the guard, especially any metal parts. Only use bleach if your dentist specifically directs it, and even then, rarely.
• Alcohol-based or colored mouthwash as a soak — these can cloud or damage the plastic over time.
• Leaving it soaking overnight in cleanser tablets — unless your dentist tells you otherwise, a long soak well past the package's recommended time can degrade some appliance materials rather than just cleaning them more thoroughly.

Also Worth Knowing

Brush and floss your own teeth before inserting the guard each night, so you're not sealing plaque and food particles against your teeth for hours. And bring the guard to your regular dental visits so it can be professionally checked and cleaned — this catches wear and fit issues before they become bigger problems.

Signs It's Time for a Replacement

Watch for visible cracks, a rough or thin-feeling surface, a fit that feels looser or different than it used to, or persistent odor or discoloration that cleaning doesn't resolve — any of these mean it's time to have it checked and likely replaced, since a worn or poorly fitting appliance is far less effective.

When to Call Your Dentist

Reach out sooner rather than waiting for your next scheduled visit if the guard no longer fits or feels loose, you notice cracks, sharp edges, or a persistent odor or discoloration cleaning won't remove, or you develop gum irritation, mouth sores, or any other sign of a mouth infection.

If your night guard or retainer isn't fitting the way it used to, bring it to your next visit and we'll take a look. Learn more about how these appliances work on our TMJ & bite appliances page.