Both of the laser you mention create small dots or mtzs (Micro Thermal Zones) of tissue injury or heating. The MTZ heal from the surrounding injured tissue so that you get a smoother, tighter more uniform appearance of the skin.
ProFractional lasers utilize an erbium laser that is very specific for water. With this laser you can remove or vaporize a specific amount of tissue giving your skin a beautiful resurfacing. You can also add heat to the columns of tissue or not depending upon what your doctor and you are trying to accomplish. Heat causes the surrounding collagen to contract.
CO2 fractional lasers utilize CO2 which has a higher wavelength of light in the Infra red spectrum. While it also uses water as a chromophore it is not as specific so the thermal relaxation time isn't reached as quickly and the tissue surrounding the MTZ absorb the excess heat. This allows for collagen contraction and again can gives the skin a nice uniform color and texture. The difficulty with the heat for both lasers is that this can cause hyperpigmentation in darker skin types or long term hypopigmentation.
CO2 has been considered the gold standard for facial resurfacing, however the ProFractional with its ability to deliver prescribed depths of tissue ablation and heat may give your provider a little more control.
I hope this helps. Often it is not the tool that matters but the person using it and the material with which they are working with.
