They are essentially the same
A better question and the one you might have wanted to ask is, what is the difference between non ablative and ablative resurfacing for the skin?
Nonablative is usually done through radiofrequency, or other wavelengths that go deeper in the skin to stimulate the deeper tissues to tighten up the skin. Wavelengths from 1300-1600 achieve this non ablative skin tightening. Radiofrequency is another way of doing this via thermage, etc. These devices although not removing the layers of the skin,...