7 min read • By Dr. Kevin Baharvand, DMD, MS • Updated August 2026
The short answer
Rinse it the second you take it out, brush it with a soft brush and mild soap rather than toothpaste, and let it dry completely before it goes in the case. Soak it in a denture or retainer cleaner once a week. Never use hot water, never use bleach, and never leave it damp in a closed case, which is the single fastest way to grow a biofilm on something you then put in your mouth for eight hours.
A night guard is a custom piece of plastic that sits against your teeth and gums for a third of every day. People treat it like a retainer they can rinse occasionally, and then wonder why it smells.
The cleaning itself takes about ninety seconds. The part that goes wrong is usually one of three things, and they are all easy to fix.
On this page
The daily routine
Rinse it under cool running water the moment you take it out, before anything has a chance to dry on it. This one habit does more than everything else combined.
Brush it with a soft toothbrush, ideally a separate one kept for this. Use mild dish soap, unscented hand soap, or a little liquid castile soap. Cover the whole surface including the inside where it contacts your teeth.
Rinse thoroughly, then let it air dry completely before the case closes. Ten to fifteen minutes on a clean surface is enough.
That is it. Once a week, soak it in a retainer or denture cleaning tablet solution for the time on the packet, then rinse well.
Why not toothpaste
This surprises people, because it seems like the obvious thing to use.
Toothpaste is abrasive by design. It is formulated to scrub a mineral surface, and your night guard is soft plastic. Over months, brushing with toothpaste puts microscopic scratches across the surface, and those scratches hold bacteria in a way a smooth surface does not. A scratched guard gets cloudy, then it starts to smell, and no amount of cleaning fully resolves it because the roughness is now part of the guard.
Same reasoning applies to whitening toothpaste, which is usually the most abrasive kind of all.
Mild soap and a soft brush clean it perfectly well without doing that.
The things that actually ruin them
Every one of these turns up regularly, and most of them are irreversible.
| Do not | What happens | Instead |
|---|---|---|
| Hot water, boiling water, or the dishwasher | The plastic warps. A warped guard does not fit and cannot be adjusted back | Cool or lukewarm water only |
| Bleach or household disinfectant | Degrades the material, can leave residue, and can bleach the guard brittle | Retainer or denture cleaning tablets |
| Toothpaste as a daily cleaner | Micro scratches that trap bacteria permanently | Mild soap and a soft brush |
| Leaving it wet in a closed case | A warm damp sealed box is close to ideal for growing bacteria and fungus | Dry completely first, and leave the case open to air |
| Alcohol based mouthwash soaks | Dries and cracks some materials over time | Water based cleaners meant for appliances |
| Leaving it on a car dash or windowsill | Heat warps it just as effectively as hot water | Store it in the case, away from heat and pets |
Dogs eat night guards. This is not a joke, it is genuinely one of the most common reasons a replacement gets made. Something that smells like you and is made of chewy plastic is a dog toy, and a guard left on a nightstand is fair game.
The case matters more than the guard
People clean the guard religiously and then put it back into a case that has not been washed since the day they got it.
Wash the case with soap and warm water at least weekly, and let it dry fully. If the case has been sitting damp, whatever is growing in there transfers straight back onto the clean guard.
Leave the case open between uses so it can dry out. A vented case helps.
If it already smells or looks cloudy
Start with a proper soak. Retainer cleaning tablets or a denture cleaner, following the packet timing, then a thorough brush and rinse.
A white vinegar and water solution, roughly equal parts, for fifteen to twenty minutes will help with mineral buildup, which is the chalky white film that builds up over months. Rinse very well afterward.
If the smell persists after that, or the guard has visible cloudiness that will not clear, the surface is likely scratched or the material has absorbed it. That is not a hygiene failure on your part and it is not fixable. It is a replacement.
The other thing worth checking: buildup that keeps returning quickly can be a sign of heavy grinding wearing the surface, or of dry mouth overnight, which changes the whole picture in your mouth and not just on the appliance.
How long one should last, and when to bring it in
With decent care, a hard acrylic guard typically lasts several years and a softer one considerably less. Heavy grinders go through them faster, which is not a defect, it is the guard doing its job instead of your teeth doing it.
Bring it to your cleaning appointments. It takes two minutes to check the fit and the wear pattern, and the wear pattern is genuinely informative. It shows where and how hard you are grinding, which is worth knowing.
Get it looked at sooner if it stops fitting, if it cracks or a hole wears through, or if you are waking with more jaw soreness rather than less. A guard that no longer fits properly can do more harm than no guard at all.
And if you have had dental work since it was made, a filling or a crown changes the shape of the tooth it sits on. Mention it, because the fit may need adjusting.
Common questions
Can I clean my night guard with toothpaste?
Better not to. Toothpaste is abrasive and creates micro scratches in the plastic that trap bacteria permanently. Mild soap and a soft brush clean it just as well without damaging the surface.
Can I use bleach or mouthwash on a night guard?
No to bleach, which degrades the material. Alcohol based mouthwash can dry and crack some materials with repeated use. Retainer or denture cleaning tablets are the safe option.
Can I boil my night guard to sterilise it?
No. Heat warps it permanently and a warped guard cannot be adjusted back to fit. Cool or lukewarm water only, and keep it away from dishwashers and hot cars.
Why does my night guard smell?
Usually bacteria in a surface that was scratched by abrasive cleaning, or storage while still damp. Soak it in a cleaning tablet solution, wash the case, and dry both completely before storing.
How often should I deep clean it?
A weekly soak in a retainer or denture cleaner, alongside the daily rinse and brush. Wash the case weekly too.
How long does a night guard last?
Several years for a hard acrylic guard with good care, less for a softer material or a heavy grinder. Bring it to cleaning appointments so the fit and wear pattern can be checked.
Bring your night guard to your next cleaning
Two minutes to check the fit and read the wear pattern, which tells us how hard you are actually grinding. If it has stopped fitting or you are waking up sorer, that is worth catching early.
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About Tribute Family Dentistry
200+ five-star Google reviews • Family owned and independent • D Magazine Best Dentist 2026 • Living Magazine Readers' Choice 2026 • Se habla espanol
Tribute is a family owned, independent practice on FM 423 in Frisco. I own it with my wife, Dr. Julia Kang, DMD, MS. We both trained at Boston University and we are both members of the Omicron Kappa Upsilon national honor society. I am a Diplomate of the American Board of Orthodontics. Day to day, most patients and their kids see Dr. Christina Pham, DMD, our general and family dentist, and oral surgery is handled by Dr. David Roberts, DDS, who has been doing it for more than 35 years. D Magazine named me a Best Dentist for 2026, and Living Magazine readers voted us Best Family Dentist in Frisco and Plano the same year.
We handle the whole family in one place: cleanings and preventive care, fillings, crowns, bridges, implants, root canals, extractions and wisdom teeth, whitening, night guards, and emergency visits. We are open Monday through Friday, 8:00 AM to 5:00 PM, we speak Spanish, we work with most major insurance plans, and we run an in house savings plan for families without dental benefits.
If you need braces or clear aligners, that is the other side of what we do. Elate Orthodontics, our sister practice, treats kids, teens, and adults out of three offices in Frisco and The Colony.
Tribute Family Dentistry
5605 FM 423, Suite 600-B, Frisco, TX 75036
Book an appointment: (469) 598-1021
About the author: Dr. Kevin Baharvand, DMD, MS is a Diplomate of the American Board of Orthodontics and a national speaker on clear aligner treatment. His clinical work was selected for the cover of the American Journal of Orthodontics and Dentofacial Orthopedics. He and his wife, Dr. Julia Kang, own Tribute Family Dentistry and Elate Orthodontics in Frisco, Texas.
