What is an ablative laser?

An ablative laser vaporizes tissue. Different lasers cause different types of ablative reactions. Er:YAG lasers, due to their very high water absorption, cause almost pure ablation with very little collateral thermal heating. CO₂ lasers have less water absorption and therefore deliver less pure ablation and have more collateral heating. This heat causes thermal damage in a positive and negative manner. An example of a positive effect is collagen contraction and new collagen stimulation. Other positive effects of CO₂ lasers are sealing of blood vessels leading to less bleeding and sealing of nerve endings leading to less pain. An example of a negative effect is hypopigmentation due to inadvertant melanocyte damage. Scarring from laser procedures is usually due to excessive collateral heating.