How to Look After Custom Whitening Trays
A custom whitening tray does one job: hold gel against the teeth, in the right place, without leaking. Everything about how well whitening works depends on that seal — which is why a tray that has been through a hot tap is no longer a whitening tray, just a piece of plastic.
Looking after them is simple, but the details matter more than with most appliances.
After every session
- Rinse off all the gel under cold water as soon as the tray comes out. Gel left to sit is the single most common reason a tray degrades early.
- Brush gently with a soft toothbrush — inside and out, including any reservoirs, where residue collects.
- Dry thoroughly before it goes away.
- Store it in its case, somewhere cool.
What ruins a whitening tray
- Hot water. The one that ends trays. The material softens and distorts, and a distorted tray does not seal — so the gel migrates where you do not want it.
- Heat generally — radiators, windowsills, a car in the sun.
- Toothpaste, which is abrasive enough to cloud the surface over time.
- Leaving gel in the tray between sessions.
- Squeezing them into a bag loose, which is how thin trays crack.
Why the seal matters so much
Custom trays are made to the contours of your own teeth and finished to sit precisely at the gum margin — ours are supersealed and scalloped, with reservoirs where controlled gel placement is needed. That design is what keeps gel on the teeth and off the gums.
Once a tray warps, all of that is lost at once. The gel spreads where it should not, results get patchy, and the usual reaction is to use more gel — which makes the problem worse rather than better. If a tray has stopped sealing, the answer is a new tray, not more product.
Between courses
If you are putting trays away for a while:
- Clean and dry them thoroughly first — not after a gap.
- Store them in the case, not loose in a drawer.
- Before starting a new course, have your dentist check the fit. Teeth shift over time, and any new restoration, crown or extraction since the trays were made will change how they seat.
A note on the gel
How much gel, how long to wear the trays, and how often to repeat a course are decisions for your dentist, not for us or for the internet. We make the trays; the whitening protocol is theirs. If something feels wrong — sensitivity, gum irritation, patchy results — that is a conversation with the practice rather than something to solve by adjusting the regime yourself.
Made in our UK lab
We make custom whitening trays — supersealed, scalloped and reservoired as standard, or finished to your prescription — in our Christchurch lab. See our cleaning guide for care across the whole appliance range, or custom whitening trays vs boil-and-bite for why a lab-made tray outperforms a shop-bought one.