Jacob asked: “Can Invisalign patients whiten during ortho by using their Invisalign trays instead of the KöR Seal Tray?”

Hi Jacob,

This question comes up over and over. Though you “can” use Invisalign trays to hold whitening gel, the results will be very inferior to what you’d achieve with a whitening tray like the KöR-Seal Trays.

Here’s the problem – For consistent truly excellent whitening results, you need a good seal at the cervical 1-1.25 of the tooth next to the gingival margin. Invisalign trays specifically do not create even close to a seal.

I’m sure you’ve heard that many studies have shown that “typical” whitening trays allow an average of 20-35 minutes of “active” whitening inside whitening trays. These studies measure the potency of the whitening gel in the middle third of the teeth at certain time intervals. So those studies have specifically shown that typical whitening trays provide 20-35 minutes of active whitening, specifically in the middle third of the teeth.

So why is that? Why does the whitening gel become inactive, or far less active, after only 20-35 minutes? There are two reasons:

  1. If you don’t have a good seal at the cervical area of the trays, the whitening gel will leak out of the trays, and be sucked out of the trays when swallowing. At the same time, saliva will get into the trays and dilute the remaining whitening gel. However, reason 2) below is a far bigger problem.
  2. If you don’t have a good seal at the cervical area, saliva will leak into the trays and be sucked into the trays. Also, sulcular fluid excreted by the gingival crevice will get under and into the whitening tray (especially if you’re covering any of the gingival margin with the trays).

Saliva and sulcular fluid are heavily concentrated with the natural antioxidant enzyme glutathione peroxidase. Sulcular fluid is even more concentrated than saliva. This antioxidant enzyme’s only job is to break down and destroy peroxide instantly on contact. So as soon as the saliva and sulcular fluid start getting under the tray, it starts destroying the whitening gel immediately. If that wasn’t bad enough, the antioxidant forces the peroxide to instantly break down to only water and molecular oxygen, which does absolutely nothing for whitening. Whitening occurs when peroxide breaks down to radicals and ions such as hydroxyl radicals, perhydroxyl radicals, and superoxide radicals. So, the saliva and sulcular fluid not only cause the peroxide to fully break down ON CONTACT, but the breakdown byproducts are not even effective in teeth whitening.

But also consider this – saliva and sulcular fluid first get under and into the tray in the cervical third of the teeth. This is where the whitening gel peroxide will be destroyed first – in the cervical area. Then the glutathione peroxidase destruction moves on to the middle third of the teeth. The point is, those studies I mentioned showed active whitening for only 20-35 minutes in the middle third. So just imagine how quickly the peroxide was destroyed in the cervical area. What, maybe 5 minutes? Even ten minutes?

If you’re like most dentists, you’ve found that many of your at-home tray whitening patients’ teeth become far less white in the cervical area than you’d otherwise expect. Sure, you already know that the enamel is thinner in the cervical, so you won’t expect as much whiteness….but I’m talking about seeing even less whitening than you’d otherwise expect. So now you know why you see such minimal whitening in the cervical area.

Conventional, or “typical” whitening trays do not effectively seal in the cervical area, which is why saliva and sulcular fluid gets under the margins of and into the whitening trays. But just think of Invisalign trays. They are far more wide-open at margins of those trays, so they let even more saliva and sulcular fluid into the trays. This is why, if your goal is to achieve truly successful whitening, I do not recommend using Invisalign trays for whitening.

As I’m sure you know, or at least have heard, KöR-Seal Whitening Trays are designed to create a seal at the cervical of the teeth, right next to the gingival margin. This allows a full 6+ hours of active whitening (compared to the average 20-35 minutes) inside the trays during sleep, with some whitening seen out to ten hours. Since the trays seal in the whitening gel, and far more importantly, seal out saliva and sulcular fluid, you’ll understand that this whitening activity goes on also in the cervical third of the teeth. So your patient achieves not only far more effective whitening, but this effectiveness also is achieved in the cervical third of the teeth.

Very best regards,


Dr. Rod Kurthy

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