I recently seen a dentist for my filling, I for the first time paid attention to what he was doing I guess, because the material he used for my filling was easily deformable before he put it on my teeth (like clay), however it was/and still is pretty solid in my mouth.

Conjecture

• I've seen him using ultraviolet laser, I presume he excited the material with UV somehow thus changed the state of the material, yet I don't know how.

I've done some search on internet yet couldn't find anything relevant.