Why Your At-Home Teeth Whitening Attempts Are Burning Your Gums

Posted on: 6 June 2023

The applicator trays included with at-home teeth whitening kits follow the one-size-fits-all philosophy. It's more accurate to suggest that one size generally fits most. Your dental arches (which are your upper and lower sets of teeth) are uniquely yours, and if the configuration of your arches doesn't match the design of the applicator trays, your teeth whitening efforts may have a potentially dangerous side effect—chemical burns.

Active Ingredient 

The active ingredient in the whitening gel you must place in the applicator trays is hydrogen peroxide or bleach. When formulated to whiten teeth, the hydrogen peroxide permeates the pores of your dental enamel, lightening the darker pigments that are causing the discoloration of your teeth. The hydrogen peroxide should only be making contact with your dental enamel—or at least, this is how it's supposed to happen.

Applicator Trays

An ill-fitting applicator tray can cause the whitening gel to leak out and be distributed across your gingival tissues and mucous membranes (the soft lining of your mouth). Whitening gel should not be making contact with these tissues. The subsequent irritation and redness is a chemical burn, and these burns will worsen if you continue using the product. In that case, what's the best way to whiten your teeth?


Teeth whitening products aren't all the same—not by a long shot. Check the fine print on your whitening gel. The percentage of included hydrogen peroxide can vary by a considerable degree (from 3% to 20%). A lower-intensity product should, in theory, trigger less irritation. However, your whitening efforts may not be as noticeable. If the shape of your dental arches means that the tray never fitted all that well to start with, your teeth whitening attempts will ultimately be unsatisfactory.

Making Contact

When the applicator tray doesn't make adequate contact with your teeth, openings will be created allowing the whitening gel to leak. Additionally, what gel remains may not be making sufficient contact with your teeth, leading to uneven results. Your circumstances don't mean that you can't whiten your teeth, but you'll need to consult a dentist who offers teeth whitening services.

Cosmetic Dentistry

In-office teeth whitening (performed by a dentist) will be your best bet. Many professional whitening is laser-activated (with the frequency of the laser triggering the potency of the bleaching agent), and your dentist can add sufficient safeguards (such as a dental dam) to prevent gum damage. To maintain your efforts at home, your dentist can make bespoke thermoplastic applicator trays. As these will be designed especially for your dental arches, leakage is no longer a problem. 

Chemical burns aren't a standard side effect of teeth whitening, so see a dentist if your applicator trays are leading to gum damage. 

For more info, contact a company like Rigby Dental.