Laser technology is being developed very quickly, as well as a better understanding of laser interaction with biological tissues, has widened the spectrum of possible applications. This article describes the principles of laser operation and the clinical application of laser technology in the different fields of dentistry. Selection of suitable wavelengths from the various laser systems available requires advanced training and an educated understanding of the different characteristics in each laser system. The purpose of this review is to describe the principles of operation and discuss possible clinical applications of lasers.