A laser is a device that delivers coherent, monochromatic
and collimated light as a form of energy. Most dental laser
devices emit invisible light in the infrared portion of the
electromagnetic spectrum. On May 7, 1997, the Food and
Drug Administration (FDA) cleared for marketing in the
United States the first erbium: yttrium - aluminum -garnet,
or Er: YAG, laser for use in preparing cavities in the teeth
of living human subjects.