I got a home tooth-bleaching kit. It includes an LED light to shine on the stuff, which I take is largely hydrogen peroxide.
I also got an ad in my FB feed for something that looks like glue (but they say this is not glue!) and after you apply you shine what appears to be an LED light on for a few seconds.
In either case, how does this light act to either bleach teeth or cure a bonding agent?
It’s UV.
There is enough energy in UV light to cure certain polymers.
I have no idea about the bleaching, though.
When I had my mercury fillings replaced they mixed up some white epoxy filled the teeth and used some UV flashlight to cure it.
Also no idea regarding the bleaching.
Although hydrogen peroxide is a natural bleach, and naturally reactive, you can make it even more so by exposing it to UV light. The UV light breaks H202 into OH & OH. (Note: not OH-).
Interesting thought: the process of breaking up molecules by exposure to UV light is called “bleaching”. So the hydrogen peroxide, which is a bleach, is bleached to form neutral OH, which is a stronger bleach.
Epoxy and similar is cured by peroxide … So the UV light cures it by making the peroxide or OH available …