To whiten teeth with a laser, first you need to apply a special gel, which in its composition contains an oxidizing agent. The laser beam drives it, due to which the oxidizing agent liberates oxygen molecules, which in its turn enter the farthest enamel salts and destroy the pigment that accumulates. Each tooth undergoes this procedure individually for 1-2 minutes, with the gums and mucous membranes being maximally covered with a special film.
You will be shocked, but literally in 15 minutes you can really find a new snow-white smile.