[Experimental study of the direct effect of CO2 laser beam on the oral mucosa].

Interferences were made with a high-energy carbondioxide laser on the tongue and buccal mucosa of albino rats. Tissue destructions -- and cryodestruction reported in the literature -- were comparatively evaluated. At the edge of the laser cut a 30 micron carbonization zone occurred, beyond this a 150 micron necrotic zone and an 800 micron transition zone were observed. These were irreversibly damaged territories with coagulated blood vessels. The surrounding was hyperaemic and edematous. The application of higher energy brings about less tissue damage with narrower zones. A similar but more widely damaged destruction occurs after electrocauterization. Here, irreversibly damaged areas are 5 to 8-times wider than those found with laser. The largest damaged area was found after cryodestruction. It is thus concluded that the use of a high-energy carbondioxide laser results in the smallest irreversibly damaged tissue area. This explains the clinical advantages of the laser knife: coagulation during cutting, reduced postoperative pain and edema, small scar and good functional and aesthetic restitution.