Most athletes assume their mouthguard takes its biggest hit on the field. The truth? The majority of mouthguard damage happens off it. In the locker room. In the car. In the kitchen. It is the small, everyday mouthguard habits that quietly shorten the life of a guard – and most athletes have no idea they are doing it.
Here is a straight-talking rundown of what can damage mouthguards, habit by habit, and exactly what to do instead.
Why Your Off-Field Habits Matter
A custom mouthguard is a precision-made piece of protection. It has been moulded to your exact teeth, built to absorb impact and keep your mouth safe during competition. That is not something you want to compromise with careless handling.
A quick note on terminology: this guide focuses on sports mouthguards specifically. If you wear a dental splint for grinding, clenching, or TMJ-related issues, the same care principles apply, but a splint is a different device. Splints are typically thicker and harder, designed to handle sustained nightly pressure rather than absorb sporting impacts. If you are unsure which type you have, your dental provider can confirm.
The problem with a damaged mouthguard is not just that it looks or feels off. A guard that has been warped, cracked, thinned, or distorted cannot absorb impact the way it was designed to. You might still be wearing it. It might still look okay from the outside. But it is no longer doing its job properly.
The habits below are the most common culprits. If you recognise yourself in any of them, now is a good time to change course.
The Habits That Are Damaging Your Mouthguard
The Hot Water Mistake
Rinsing your mouthguard under the hot tap feels like good hygiene. It is not. The thermoplastic material used in custom mouthguards is designed to be heat-sensitive. That is how it gets moulded to your teeth in the first place. Expose it to hot water regularly, and you will gradually warp the fit, making it looser, less effective, and uncomfortable.
The fix: always rinse with cool or cold water only, straight after use.
Leaving It in a Hot Car
This one catches a lot of athletes out, especially in the Australian summer. A car left in the sun can reach temperatures that will warp a mouthguard in minutes.
Dashboards and back seats in direct sunlight are among the worst places to leave one.
The same applies to any hot environment: a warm gym locker, a sunny windowsill, or on top of a heater.
The fix: store your mouthguard in its case, in a cool spot away from direct heat and sunlight.
Tossing It Loose in the Sports Bag
The sports bag is one of the most hostile environments a mouthguard can end up in. Loose in the bottom of a bag, it gets crushed by boots, snagged by studs and buckles, exposed to bacteria from sweat-soaked kit, and very often lost entirely. A guard that lives loose in a bag will not last the season.
The fix: always store it in a vented hard case. It takes five seconds. For a full rundown on storage and cleaning, see our mouthguard care guide.
Chewing or Biting Down on It
A surprisingly common one. Many athletes absentmindedly chew on their mouthguards on the bench, during warm-ups, or in the changing rooms. Each bite creates micro-tears and bite marks in the material, gradually thinning the guard in the exact spots that need to be thickest for impact protection.
Once those high-stress areas are compromised, the guard cannot protect your teeth and jaw the way it should.
The fix: wear it correctly during play or take it out entirely. Do not use it as a chew toy.
Cleaning It With Toothpaste or Harsh Products
Toothpaste is abrasive. On teeth, that is useful. On a mouthguard, it scratches the surface and creates tiny grooves where bacteria embed themselves, and the material degrades faster. Strong alcohol-based mouthwashes have a similar effect – they dry out and weaken the material over time, leading to cracking.
The fix: rinse with cool water and use a soft toothbrush with mild, non-abrasive soap. More details in our mouthguard care guide.
Sharing It With a Teammate
It might seem obvious, but it happens. A custom mouthguard is moulded to one specific set of teeth. Putting it in someone else’s mouth distorts the fit for both people, transfers bacteria, and means neither athlete is getting the protection the guard was designed to provide.
The fix: one mouthguard, one athlete. No exceptions.
Using a Damaged Mouthguard Past Its Life
A worn-out mouthguard can create a false sense of security, which in some ways makes a damaged mouthguard more dangerous than no guard at all. If you notice any of the following, it is time for a replacement:
- Visible cracks, tears, or bite marks in the material
- Noticeable thinning in any area of the guard
- A loosened or ill-fitting feel that was not there before
- Persistent bad odour that does not go away after cleaning
- Any discomfort or pressure points that have developed over time
The fix: do not try to patch it up or push through another season with a compromised guard. Replace it.
How Long Should a Custom Mouthguard Last?
With the right mouthguard habits in place, a well-maintained custom sports mouthguard will typically last one to two full seasons for adults. For younger athletes, the timeline is shorter. Children’s jaws and teeth change quickly, which means a guard that fits well at the start of the year may no longer fit correctly by the end of it. Our kids mouthguards should be checked and replaced more frequently to keep up with growth.
For night guards, lifespan depends heavily on the severity of grinding. Heavy grinders may find they need a replacement sooner, as the material wears faster under sustained pressure.
Across the board, the single biggest factor in how long a mouthguard lasts is how it is treated between uses. The habits above are the difference between a guard that goes the distance and one that is replaced before the season is out.
Is Your Mouthguard Already Showing Signs of Damage?
If you have spotted a few familiar habits in the list above, you are not alone. These are the things nobody tells you when you first get fitted, and most athletes only find out when the damage is already done. The important thing is catching it now.
If your guard is already cracked, warped, or no longer fitting the way it used to, do not wait until next season to deal with it. A compromised mouthguard is not worth the risk. Check out our FAQ page if you have questions, or head straight to how it works to see how quick and easy it is to get a new one fitted.
Ready for a replacement? Get in touch with the team, and we will sort you out.
