How to Clean a Mouthguard

Why a mouthguard goes bad

The same three conditions that ruin boxing gloves: moisture, no airflow and time. A guard comes out of your mouth coated in saliva, goes into a closed case while still wet, and then sits in a warm gym bag for a week. What you notice first is the smell and a cloudy film on the surface; what you do not notice is that the routine which produced that is also the one slowly degrading the material.

None of this needs a product. The American Dental Association's published care guidance for mouthguards is four lines long — rinse before and after each use or brush with a toothbrush and toothpaste, clean regularly in cool soapy water and rinse thoroughly, store and transport it in a sturdy vented container, and never leave it in the sun or in hot water. That is the entire method, and it works.

The forty-second routine

The numbered steps above are the full version. In practice, the habit that does nearly all the work is this: the moment the session ends, rinse the guard, brush it, shake it off, and leave the case open while you change. By the time you are ready to leave, it is dry enough to put away. The guards that go bad are almost always the ones that went from a mouth into a sealed box inside ten seconds.

The weekly clean, for a guard that already smells

Cool, soapy water and a soft brush, worked into every channel, then rinsed until no soap taste is left. Let it air-dry fully before it goes away. If your guard has a case with a vented lid, leave the case open in a dry room rather than in the bag.

You will find plenty of soak recipes online — vinegar, hydrogen peroxide, denture tablets, mouthwash. We are not going to publish measurements for any of them, because the ADA's own guidance does not, and the one thing all of them have in common is that they are solving a problem that drying the guard properly would have prevented. If a guard has gone genuinely foul, the honest options are a dental cleaning at your next checkup — which the ADA suggests, and dentists can do thoroughly — or a replacement, which on a boil-and-bite guard costs less than most people think.

What ruins a mouthguard

Boil-and-bite, custom and remoldable guards

The cleaning routine is the same for all of them; the heat warning is not. A standard boil-and-bite guard is a one-shot fit — heat it once, bite it, and from then on heat is the enemy. A remoldable guard is designed to be refitted multiple times, so a distortion is recoverable by refitting it to the manufacturer's instructions rather than binning it. A custom guard from a dentist is the most expensive thing in your kit and the one most worth taking to a checkup for professional cleaning.

If you are not sure which you have, the fitting instructions that came with it tell you, and how to fit a boil-and-bite mouthguard walks through the process — including what a correct fit feels like, which is the thing you are checking for when you inspect a guard that has been through a hot wash.

When to replace it instead

The ADA's position is the sensible one: check the fit and check for wear and tear, and replace the guard when either has gone — and replace it immediately if it is damaged or no longer fits. Children and teenagers need replacements more often because their mouths are still growing, which is worth knowing if you are the parent buying.

In practice, for an adult boxing once or twice a week, the signs are: visible thinning or tooth marks chewed through the bite surface, a tear anywhere, a guard that no longer clicks onto the upper teeth and stays there without being held, or a smell that survives a proper clean. None of those are cleaning problems. Our best mouthguard for boxing roundup ranks the replacements, and if there are braces involved, the braces roundup is the right list — a guard fitted over braces is replaced on a different schedule entirely.

Do you even need one yet?

If you are hitting a bag in a garage, no — a mouthguard is sparring equipment, and it is the first thing you buy when sparring starts, before headgear. When do you need boxing headgear covers that order, and the first sparring kit checklist is the whole list. The reason it matters here is simple: a guard you bought two years ago for a class you took twice is exactly the guard that needs replacing rather than cleaning.