At a glance
- You need: a ceramic bowl, freshly boiled water, a spoon, a timer and a mug of cold water
- Softening time: 20 seconds for OPRO Gold, Silver and Bronze, and 30 seconds for the OPRO Instant Custom
- Bite: firmly for at least 30 seconds, ideally 60
- Set and rest: 30 seconds in cold water, then rest before first use
- Always: check the instructions in the pack, as timings differ between makes and models
A gumshield only protects properly if it fits properly. A guard that is too loose can move or fall out, and one that is moulded badly may not cover the teeth as it should. The good news is that boil-and-bite guards are easy to fit at home, and most people get a good result first time if they follow the steps carefully.
This guide uses OPRO's published fitting steps as an example, because we stock their self-fit range. If you have a different make, such as Gilbert or Shock Doctor, use the instructions that come with it, because timings and methods can differ.
What you need
- A ceramic bowl. OPRO advises against plastic or metal.
- Freshly boiled water.
- A spoon, to lift the guard out of the water.
- A timer, because the time in the water matters.
- A mug of cold water for setting the guard.
If your guard comes with a compression cage, practise putting the cage in your mouth a few times before you start, without the guard in it. That way you know what to do when the guard is soft.
Step by step
- Soften the guard. Pour freshly boiled water into the bowl and put the guard in straight away. Leave it for 20 seconds, or 30 seconds for the OPRO Instant Custom. Do not leave it in for longer.
- Cool it slightly. Lift it out with the spoon, turn it upside down to drain, and shake it for up to 10 seconds. It will be hot, so let it cool before it goes anywhere near your mouth. You can blow on the fins to cool them further.
- Position it. On Silver and Gold guards, sit the guard centrally in the compression cage and place the cage in your mouth. On a Bronze guard, use the fitting handle to put it in the centre of your mouth.
- Bite. Bite down firmly and evenly for at least 30 seconds, and ideally 60. On a Bronze guard, push your lips and cheeks with your fingers while you bite. Do not bite so hard that you cut through the material.
- Set it. Take the guard out and put it in cold water for 30 seconds.
- Let it rest. Leave it in the fridge for 15 minutes, or at room temperature for an hour, before you wear it for the first time.
Common mistakes
- Leaving it in the water too long. The wrong time can damage the guard.
- Biting too hard. You can bite through the material, so firm and even is enough.
- Wearing it too soon. Let it rest before first use, as in step 6.
- Using heat later. Do not put a guard in the dishwasher, because the heat will damage it.
- Choosing the wrong type. If you wear fixed braces, choose a braces model rather than a standard one.
If the fit is poor, you can usually mould the guard again by repeating the steps. If it still does not fit, contact the maker, as OPRO offers a Precision-Fit Guarantee. Please remember that self-fit guards cannot be returned to us once they have been opened, so choose the right size and type before you start.
Which guard is right for you?
| Guard | Sizes | Good to know |
|---|---|---|
| OPRO Silver Self-Fit | Junior and Adult | OPRO's match level guard, with stretch zones to help it stay in place. |
| OPRO Gold Self-Fit | Junior and Adult | OPRO's competition level guard, with dual layer protection and antimicrobial protection. |
| OPRO Gold Braces Self-Fit | Adult only (10+) | Suitable for people with fixed braces. |
| OPRO Instant Custom Self-Fit | Junior and Adult | Triple layer construction and patented fin technology. Softens for 30 seconds rather than 20. |
We also stock the OPRO Bronze Self-Fit and guards from Gilbert, Grays and Shock Doctor. You can see everything in our mouthguards collection.
Buying for a team or school
If you are kitting out a squad, it helps to know each player's size and whether anyone wears fixed braces before you order. Dental bodies recommend mouthguards for school-age players in contact sports, and competition rules vary, so check the requirements for your league or school fixtures. If you are buying for a team or school and would like help choosing, we are happy to advise.
Need help choosing?
Coaches and teachers: buying gumshields for a squad?
Email sales@martinberrillsports.com with the number of players, their ages and whether anyone has braces, and we will help you choose the right guards.
Quick answers
Can I fit it again if it does not feel right? Usually yes. Repeat the steps. If it still does not fit, contact the maker.
Can I return a guard once I have opened it? No. Self-fit guards cannot be returned once opened, so check the size and type first.
Is a boil-and-bite guard the same as a dentist-made one? No. A dentist can make a fully custom guard. A boil-and-bite guard is moulded at home, which is quicker and costs less.
Fitting steps and timings follow OPRO's published guide for its Instant Custom, Gold, Silver and Bronze guards. Other makes and models differ, so always follow the instructions in the pack. Product details are taken from our listings and were checked in October 2026. This guide is general advice, not dental advice.