I've recently starting light sparring (Muay Thai and Boxing) and use one of those single boil+bite style gum shields.

How often should I need to re-mould it as it seems to have lost it's fit after just a few weeks? Is this normal?

Also, should I really use a double gum shield for boxing - even if it is just light contact training?

  • I have a fitted upper and a fitted lower. They are great and comfortable after getting used to a mouthful of plastic. Used them for years. recommended.
    – user5931
    Jun 12, 2015 at 15:21

6 Answers 6


In a perfect world, your mouth guard should fit for the life of the guard if properly molded in the first place. It is extremely common, however, to have a mouth guard that doesn't properly retain its shaping, mostly because of a relaxation or remodeling of the guard from wear, being cleaned with too high of heat, or simply from never having been properly shaped in the first place.

Boil and bite mouth guards are generally better than the cheaper "uniform fit" style, but if improperly fitted in the first place may not last long at all. For clarity, and in case some step was ignored, try these steps for fitting a mouth guard:

  • Boil a pot of water and prepare a cup of cool water.
  • Drop in the mouth guard, gently using tongs to push it about so it does not lay flat against the bottom of the pot (which can cause deformations). Allow to boil for 30 seconds.
  • Gently, with minimal pressure, remove the mouth guard from the boiling water and submerge in the cool water for about 5 seconds. The guard should be warm but comfortable to touch.
  • Remove from the cool water and push the guard over your teeth, applying pressure with your fingers to mold to the shape of you mouth.
  • Close your mouth without closing your teeth and suck to remove air and water from within the mouthguard for about 40 seconds.
  • Finally, bite down for about 20 seconds to set the mouth guard the rest of the way.

Ideally, following these steps will give you a good, near-custom fit that lasts. You should, at the least, be able to get a couple of months out of a guard at the very least, but likely more. You may want to familiarize yourself, however, with how often one should change their mouth guard.

The double mouth-guard may or may not be a good option. The most important function of the mouth guard is to keep the teeth from slamming into each other, causing a shock to reverberate through the mouth and skull which could cause damage to the teeth, sinuses, ears, and brain. A single mouth guard is generally sufficient for this, and may provide a better fit for people with misaligned bottom teeth. The straighter your bottom teeth, the more likely a double mouth guard will be of use to you.

  • 1
    +1, but I wanted to add that the mouth guard will generally have to be reformed after any dental work of note (e.g. some fillings, crowns, etc) and that depending on your age your teeth have a natural tendency to have some "drift" which can cause the fit to change.
    – anonymous
    Feb 7, 2012 at 12:34
  • This is also the reason the boil and bite mouth guards tend to be more popular than dental injection molded custom fabricated guards. They're prohibitively expensive for most purposes, and not worth the cost difference when the boil and bite offer equivalent protection, if less permanent fit.
    – stslavik
    Feb 7, 2012 at 19:13

I would advocate that you throw the boil & bite mouthguard away and spend the money to get a properly moulded one from your dentist or orthodontist. The advantage these have is that they are moulded very closely to your teeth, and they are very hard to dislodge. Consequently you don't end up distracted by it while sparring and don't end up gagging from it moving around your mouth. You should also be given a moulded mount to put the mouthguard back on when its not in use so that it doesn't get squashed or deformed between trainings.

These are considerably more expensive than they common boil & bite variety, but ask yourself this question: how much would it cost to get your teeth reconstructed because you used a cheap (crap) mouthguard compared to how much it would cost to get a properly moulded/fitted mouthguard?

With some safety or training equipment you can cut corners on quality and cost, your mouthguard shouldn't be one of those.

  • 1
    The boil & bite mouth guard do not offer significantly less protection than the dental manufactured, and at a significantly less price, tend to be a far superior solution for the avid amateur. If you're a professional athlete making 8 figures a year, it's reasonable; if you're like me, you stick to the off-the-shelf variety and learn the best ways to make them work.
    – stslavik
    Feb 7, 2012 at 19:16
  • The self forming boil and bite ones that I've bought conform very well to my my mouth. So much so that they don't move or fall out when I'm moving a lot, or breathing deeply. Would an orthodontist one be recommended for everyone, or just people with special dental conditions, i.e. false teeth, bridges, etc.
    – Swift
    Feb 7, 2012 at 20:27
  • 1
    @stslavik, I paid the equivalent of approx US$50 for my moulded mouthguard (and dentistry is expensive in this country), and it is still serving me well a decade later. I'm not slagging the boil & bites, but after going through many of them with my kid who plays rugby I know the different brands have differing quality and the moulded ones are a good investment if you can afford it.
    – slugster
    Feb 7, 2012 at 21:23
  • 1
    @Swift, everyone has a different shaped mouth - you might be lucky to have a reasonably well formed teeth and gum line so you don't have too many problems with the boil & bites. Because the moulded ones are made to fit your specific teeth structure they are good for people with not-so-consistent teeth/gum structure. With mine I could jump round like a crazed monkey and it wouldn't move.
    – slugster
    Feb 7, 2012 at 21:27
  • @slugster Good to know, thanks! I have a friend with a smaller mouth and he has some issue with fit on the self forming ones. I'll pass your suggestion along.
    – Swift
    Feb 7, 2012 at 21:28

The boil and fit mouth-guard, once it's fitted properly, should not loose it's fit, especially not that soon. Some wear and tear can cause it to become a little loose over time. I've had mine for a couple of months and it still is well fitted to my upper teeth. Mine is one of those clear rubbery ones that cost like 2 bucks. You might want to try fitting another one as that one could be bad.

More general mouth-guard selection information:

There are two mouth-guard types, single and double mouth-guards. Single mouth-guards protect your upper teeth and double mouth-guards protect both your upper and lower teeth.

Single Mouth-guard benefits:

  • Lighter weight
  • Well forming
  • Cheaper
  • Smaller size and profile

Double Mouth-guard benefits:

  • Prevents less jaw movement
  • Thicker/Stronger
  • Knockout/Concussion Mitigation*
  • Decreases jaw movement

*I've heard many times that double mouth-guards help mitigate 'button' knockouts by removing additional jaw movement, but I honestly don't thinks that is completely true, just based on my medical knowledge.

Both a single and double mouth-guard will help protect your upper teeth and only a double mouth-guard will protect your lower teeth. Normally this isn't an issue as your lower teeth have a much smaller profile and are less likely to get knocked out. Both mouth-guard types will keep your teeth from slamming into each other, but the double mouth-guard will provide a little more protection in this area due to it's increased profile, decreasing the amount of vertical jaw movement.

My major issue with double mouth-guards is that they have a small breathing channel, compared to your normal unobstructed mouth. This decrease in tidal volume could pose some issues when your really sucking wind and impact air exchange. Personally a nice single mouth-guard well formed to you upper teeth will provide all the protection you need, while not decreasing your tidal volume. I use a single guard for all MMA activities and when I Airsoft. Take good care of them, cleaning them off and follow @stslavik post for changing your mouth-guard out.


Boil and Bite are ok, better then nothing. But like others have mentioned, not as good as a custom fit one you can get from your dentist. Or from a company like smart guard, or one of the many others around. My first mouth guard was a top of the line shock doctor, which are arguably one of the best brands of boil and bite. it fit ok, but came loose easily, and was a bit bulky.

I wouldn't bother with a double mouth guard, it's quite rare to have your bottom teeth knocked out, and the breathing restrictions and uncomfortableness of them makes it not worth while (to me anyway).

Price wise, a shock doctor boil and bit will cost you about 30 bucks, you can get a custom fit smart guard (or similar) for about 70. which is twice the price, but really, 30-40 bucks is nothing when u realize how much nicer the fit is, and how much less bulky it is.

I use my custom fit mouth guard for muay thai, boxing, mma, and bjj.


You should remold your mouth guard every month, and you'll be fine. This is normal. I spar as well in tae kwon do.


Don't use the double mouth guard unless you absolutely have to. It's slightly harder to breath with it. While you won't notice the difference in a 1 or 2 round fight, you'll definitely feel the prolonged effect of oxygen deprivation if you have to fight more than two fights on the same day.

As for how often you need to remould it: anytime it feels uncomfortable. It works best when it fits properly. If you have to boil and mould it after every fight, then do it. If you only have to boil and mould once a month, then do that. I had one of those EXTRA cheap ones that tasted vaguely of mint (quite nice actually) which I had to mould on a weekly basis. It was a bit of a chore, but it did its job very well.

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