eli5: How does dental filling become hard under UV light?

Question

eli5: How does dental filling become hard under UV light?

In: 17

Answer 1

Dentist here. I can’t answer the specifics of how the photoactivator compounds work, but just wanted to add that we actually don’t use UV light anymore – it’s been blue light for at least the past 20-30 years now (~470-480nm wavelength).