What exactly is density therapy?

I understand that density treatments are gaining popularity these days. As we age, there is a steady stream of talk about improving wrinkles, which were once considered a nuisance. I, too, would like to follow this trend and improve my wrinkles.

I want to know how it is different from the existing lifting treatment. It is introduced as high frequency focused ultrasound, but this term alone is not easy to understand at first glance. It increases skin density and improves the skin's elasticity.

It is said to have an elasticity-giving effect, but I wonder if this can have a permanent effect.