eli5: teeth whitening kits


Can anyone explain to me how the teeth whitening kits that shine a bright bluish/purple light on you teeth work? How do they make your teeth whiter?

For example, “Smile” was a popular one there for a while, and I believe Crest has one now as well.

I assume that they must work… otherwise someone would have surely compared their teeth from a month before treatment to after and figured out there wasn’t a change.

So how does that all work??! If someone can explain the science behind all that, it would be awesome!

I attempted to search for some sort of answer on this forum for something similar, haven’t found anything. If there is one, please let me know. I’ll be sure to take this one down!


In: Technology

It’s basically bleach, usually peroxide based.

Oxygen transfers from the peroxide and attaches to stuff that stains teeth breaking it up and fading the color.

The kits that come with lights use UV light to make the process happen faster, in a similar way that heating chemicals tends to make for a faster reaction. They still rely on a paste of some sort though. Definitely works well in a dentist’s office, but I personally have no idea if the UV light in at home kits actually does anything.

The dentist light is going to be a lot more intense, and a more energetic wavelength of uv is used that requires eye protection. The at home kits light is going to be safer and weaker so it really might just be a gimmick, and the kit may work just as well without the light.

They do work though the effect is going to be a lot better if you only want to go from heavily stained to lightly stained. Getting to pure white is usually pretty difficult. Especially because if you use the kits too often they can weaken your teeth pretty badly.

Pretty sure it has to do with peroxide. Peroxide if you’ve ever bought it comes in opaque containers.

The reason is that the bonds in hydrogen peroxide are so weak, that shining light on it can turn it back from H202 into water (H2O)

Peroxide + strong light = faster cleaning as the breakdown happens faster.