After Using Crest Whitestrips, How Long Until I Can Eat Coloured Foods?

If some of the bleaching gel gets around the tray and stays on the gums it can burn the tissue.  The good news is that it will heal quickly.  You can try drying the tissue and placing some vitamin E gel (break open a gelcap) or just ibuprofen if it is really painful.  If it's not...

White spots that appear on teeth after bleaching can occur when there are hypocalcifications (under mineralized tooth enamel) on teeth prior to bleaching. This is more common on younger teeth that may have been exposed to too much fluoride. They tend to fade somewhat and will not apppear as...

Unfortunately I see this all too often especially with young adults (kids) that don't take care of their teeth while having braces.  Simply whitening the teeth generally does not take away the "staining".  Most of the time it s bright white area on the tooth or a decalcified area....

Absolutely, you can have your teeth whitening if you have a permanent retainer. Teeth whitening gel is placed only on the front side of the tooth. The retainer on the back of your teeth should not get in the way of  the whitening process in any way. So go for it. Whitening...

Whitening during invisalign can be done inside your trays.  If you are button free for a time period you can whiten with another product and not worry that it is going to be a problem.

The white spots will get whiter and the regular teeth will get lighter as well.  Neither of them will be permanent.  No whitening is permanent that is currently available and probably will never be.