How to Mold a Mouthguard

Mouthguards are a wonderful invention for people who have mild sleep apnea or who need a solution for snoring-related problems. Having a partner who snores is no walk in the park, especially if you’re a light sleeper that wakes up at the faintest noise. But mouthguards are also here to address other problems, like teeth grinding that can cause jaw or tooth damage. So, if you have any condition or problem that might require the use of a mouthguard, this guide will show you how to mold it for a better fit.

Important Considerations

female putting in mouthguard

There are three main types of mouthguards: stock, boil-and-bite, and custom-made. The latter option doesn’t require any molding on your behalf, as the dentist takes an impression of your teeth and a laboratory makes the mouthguard. However, with stock and boil-and-bite mouthguards, you are going to have to do the work.

Because of that, we’ve divided this tutorial into two parts: we’re first going to talk about how to adjust a stock mouthguard, and in the second part we’re going to go through the step-by-step process that you have to follow in order to mold a boil-and-bite mouthguard.

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What You’ll Need to Mold a Stock Mouthguard

Stock mouthguards are ready-made products that you can take out of the package and start wearing. However, these mouthguards often receive a lot of complaints on behalf of customers who find them uncomfortable because they can’t be adjusted. Truth is, you can make some minor adjustments even to such a product. You’ll need:

  • A stock mouthguard.
  • A solid pair of scissors.

Step-by-Step Process for Molding a Stock Mouthguard

Step #1: Initial testing

  • Of course, there is always the possibility that your stock mouthguard fits like a glove and doesn’t require any trimming, and that’s something that you’ll first have to test before proceeding to the actual cutting part.
  • Take the mouthguard out of its original package and put it in your mouth, as advised by the instructions.
  • Make sure that it sits over your teeth. Touch it with your tongue and notice how it feels. Press the outside of your cheeks with your fingers to get a better sense of its position because if you sleep on the side, you want to know what compression does to your level of comfort.
  • If you notice that the mouthguard is pressing against the back of your mouth or if you get a sense of discomfort that you can’t bear, it means that you have to trim the piece.

NOTE: Feeling some mild discomfort is perfectly normal the first few times you wear a mouthguard. It is a large oral appliance that takes up considerable mouth space and it takes a while to get used to the feeling of wearing it on a constant basis.

Step #2: Trimming

  • Take the mouthguard out of your mouth and grab a solid pair of scissors.
  • Trim the extremities of the mouthguard with about 0.2 inches at each edge.
  • For comfort, it’s best if you try to cut on an angle, and make sure that the ends of the mouthguards are of the same length.
  • If you bite down on the mouthguard and you can see the impressions left by your teeth, start cutting the end part that doesn’t have that impression. The idea is that you will need the mouthguard to go as far as the length of your teeth and everything else is excess material.

Step #3: Re-testing

  • When you’re done trimming, put the piece back in your mouth and repeat the process under “Step #1”.
  • If you notice that the mouthguard is still pressing against the back of your mouth, remove it once again and trim the edge a bit further.
  • If the mouthguard has the proper length, then it should be able to cover at least your second molars.

What You’ll Need to Mold a Boil-and-Bite Mouthguard

Boil-and-bite mouthguard already has a pretty suggestive name. They are between the concept of a stock and a custom-made mouthguard. They have gen upper linings that, once heated, can be molded to the impressions of your own teeth.

Every decent boil-and-bite mouthguard should come with a set of instructions that teach you how to successfully complete the process, but we’re also going to go over those steps because they are pretty standard regardless of the brand of mouthguard that you purchase. For adjusting a boil-and-bite mouthguard, you will need the following:

  • For boiling water on the stove: a saucepan that’s deep enough to be filled with water to completely cover the mouthguard.
  • For boiling water in the microwave: a bowl that microwave-safe and can hold enough water to submerge the mouthguard.
  • A pair of tongs or a slotted spoon.
  • A mirror.
  • A dry and clean tower.
  • A bowl of cold water.

Step-by-Step Process for Molding a Boil-and-Bite Mouthguard

Step #1: Boiling the water

  • Fill the saucepan with enough water to be able to completely submerge the mouthpiece later on. Place the saucepan over medium heat and bring the water to a boiling point. When the water is boiling, remove it from the stove.
  • Alternatively, you can also use a microwave to boil the water needed to soften the mouthpiece. You will have to use a recipient which is both microwave-safe, as well as capable of fitting the entire mouthguard.

Step #2: Softening the mouthguard

  • The next step requires that you place the mouthguard inside the boiling water, making sure it’s fully submerged so that it can heat evenly. To make sure that you don’t touch the hot water or drop the mouthpiece from high above and cause boiling water to splash all around, use a slotted spoon or pair of tongs to place the piece inside the water recipient.
  • Make sure that you leave the piece inside the water EXACTLY as you’ve been instructed by the manufacturer. A lot of mouthguards only need about 30 minutes of boiling water exposure to be ready for adjustment, but every brand should provide you with this information.
  • Once the time is up, use the tongs or the slotted spoon to remove the mouthguard from the boiling water and place it on the clean and dry towel. Leave it there for about 20 seconds, just so it can cool off a bit before you put it in your mouth.
  • You can also pat the mouthguard with the dry towel in order to remove any excess boiling water that might burn your mouth.

Step #3: Fitting the mouthguard

  • Sit in front of the mirror and put the mouthguard in your mouth. Make sure that it is placed correctly around the teeth.
  • Pay close attention to the time, as you will only have about 30 seconds to bite down the mouthguard firmly to leave an impression. If too much time passes, the material of the mouthguard will cool down and harden again.
  • With the help of your fingers and tongue, make sure that the mouthguard is positioned correctly. Once in a correct position, bite down the mouthguard so that you can leave an impression of your lower teeth as well. You will need to bite for about 20 seconds or as per the manufacturer’s instructions.
  • As you’re biting down the mouthguard, try to suck out any excess water to make it a better fit.
  • When you’re done, remove the mouthguard and put it inside the bowl with cold water so that it can harden and have your impression sealed into the material. That should take about 30 seconds.

NOTE: If you don’t get it right the first time, almost every other boil-and-bite mouthguard can be readjusted as needed. You will simply have to go through all the steps again to soften the material to give it another shot.


Molding a mouthguard isn’t a complicated process, although the best and most comfortable option will always be the purchase of a custom-made piece. However, there are a lot of people that don’t want to pay such a high price or don’t have the money for it, as a custom-made mouthguard can cost hundreds of dollars.

You always have the option of buying a really good boil-and-bite mouthguard for less than $50, or even a stock mouthguard that you can trim for way less than that. What’s important is that you find a piece that you’re comfortable in wearing, whether you have bruxism, sleep apnea, a tendency to snore, or require protection from injuries when practicing certain sports.