Hot — but not boiling — water (170° F / 76° C)
Fork or similar utensil


1.Wash your hands and the material with soap and water.

Water Temperature

2.Heat water in a small bowl to approximately 170° F / 76° C (hot to the touch, but not boiling).

Step 2 - Lift the SISU

3.Place your SISU into the hot water and wait until it becomes soft and pliable (use a fork or other utensil to determine mouthguard softness).

Step 3 - Insert your SISU

4.Once soft, carefully lift the SISU out of the water with a fork. It’s essential that you do not let the softened guard fold on itself. The material will glue together, making it difficult to reshape.

Step 4 - Mold your SISU

5.Balancing the pliable mouthguard with your thumbs, tilt your head back and open your mouth widely. Using a mirror, insert the mouthguard and bite down gently on the solid bar in the middle of the SISU – just enough to keep the guard in place.

Step 5 - Check your fit

6.Press your tongue to the roof of your mouth while flipping up the softened material to your front teeth. Then starting at the back of your mouth, use your fingertips to mold the material up against your teeth moving from back to front – covering the outside of your teeth to create a solid shield.

7.Once the material is completely molded, close your lips over the mouthguard and gently suck in air until the material has hardened to a snug, perfect fit.

Did you mess up? Unhappy with your fit? Had so much fun that you want to do it all over again? NO PROBLEM! Every SISU guard is remoldable up to 20 times. Simply place your formed SISU back in the hot water, let it soften and straighten out, and there you go! Time for Round 2.

Here’s a list of things to consider when fitting your SISU!


  • Use water that is hot to the touch to activate your mouthguard
  • Mold your SISU around all of your teeth (including molars)
  • Mold and stretch the material to cover entire tooth surface area
  • Suck in air gently, creating a snug but still comfortable fit

Don't do this:

  • Use boiling water to mold your SISU!
  • Leave your back teeth exposed!
  • Overly stretch the material, creating too-large perforations
  • Suck-in air too enthusiastically, creating a fit that's too tight

Check your fit:

So you've fitted your SISU, and you're ready to hit the field...not quite. Once you've fitted your SISU Mouthguard it's important to check to make sure that it's fitted properly. A proper fitting guard is essential for the Diffusix Technology in the mouthguard to function. Here is a quick checklist.

Should you encounter a problem at any point during the fitting process, please contact our team at

Tips for fitting with children:

There is a learning curve when fitting your SISU Mouthguard for the first time. No worries, this can be made easier when you do a couple of things first:

  • If your child has braces, use the adult Aero guard regardless of their age and follow the directions for fitting with braces
  • Watch the video tutorial‚Äč with your child
  • Allow ample time for fitting (we recommend two days before needed if possible).
  • ‚ÄčIdentify the bite pad on the guard, and practice aligning it with the teeth before softening the guard for the first time.
  • The guard is formed by using vacuum pressure (suction). Re-familiarize your child with the concept of suction; grab a straw and practice.
  • If you become frustrated. Stop and take a break! Call us for help or refer to the numerous other fitting videos on YouTube.
Fitting Image