I am using whitening strips that supposedly fit around your teeth. They have whitening gel on them. Now, the whitening strips do not fit around my bottom teeth, as I have a permanent retainer behind my front bottom teeth which the strips cannot fold over. As a result, part of the gel is exposed, and comes into contact with my saliva and tongue, thus, causing me to swallow it. Is this unsafe? Should I not use this teeth-whitening method?
Teeth Whitening
Advices about the best teeth whitening products
If you want to avoid this possible problem you can skip the strips and get a whitening product that comes in a pen like applicator. You just put it directly on where you want to whiten.
The active ingredient is hydrogen peroxide. if ingested in large quantities it could be dangerous but the amount of hydrogen peroxide on the strip is in such low quantities that it won’t harm you.
You will likely feel a burning if too much gel reaches your tongue. If you do feel a burning you may want to just try a “milder” version of the white strips. Crest has about 5 different versions that vary from 10%-25% Hydrogen Peroxide.
There is a lot more information at http://freeteethwhiteningreviews.com