Effect of CO2 laser beam angle of incidence in the oral cavity

In the oral cavity of white rats a series of experiments were made by CO 2 laser beam, by handpiece, micromanipulator, and an operation microscope. The authors examined the extent of the damaged tissue on the surface and in the depth of the wound. They established that in the case of 90 degrees angle of incidence--same power, exposition time and focus--the laser beam caused the deepest crater and the least damage to the surface. The decrease in the angle of incidence caused a decrease in the depth of the laser crater and increase in the surface. The 90 degrees angle of incidence CO 2 laser beam gives the optimal possibility for the precise elimination of the pathologic tissues on the surface and in the depth, without damaging the surrounding healthy structures. This operation not only protects the normal structures but also defends the physiological functions. In cases where it is not possible to apply the CO 2 laser beam at a minimum of an incidence of 60 degrees --the indirect way--the reflection has to be chosen. These aspects are important not only in the oral cavity but in other CO 2 laser operations.