[General principles and applications of the laser]

This article defins the laser radiation, compares it with the sunlight and studies its production, describing the general principles of the laser. The different types of lasers are considered as well as their respectives applications which derive from the four ways of tissues interactions: photothermical, photochemical, photophysical and photobiological. A three laser system (CO2 laser, Helium-Neon laser and Argon laser) is proposed to the dental surgeon.