The term laser is an abbreviation for light amplification by stimulated emission of radiation. Albert Einstein first postulated the stimulated emission theory that describes the manner in which lasers produce light energy. The light produced by lasers is monochromatic, highly focused, and of a specific wavelength.
Laser systems are composed of an active medium, an external power supply, an optical resonator, a cooling system, a control system, and a delivery system. The active medium of a laser can be a solid or a gas. Lasers are named by their active medium. The active medium of an Er:YAG laser is erbium, yttrium, aluminum, and garnet. The active medium of an Er,Cr:YSGG laser such as the Waterlase MD by BIOLASE is erbium, chromium, yttrium, scandium, gallium, and garnet. The active medium of these lasers is a solid.
When energy is introduced into the active medium of a laser, monochromatic light energy of a specific wavelength is emitted from the active medium and transferred to the target tissue through the laser's delivery system. Most lasers produce light that is found in the visible and infrared part of the electromagnetic spectrum. Lasers exhibit specific properties depending on their position in the electromagnetic spectrum. The wavelength of diode lasers ranges from 812 nm to 980 nm and the light energy of a diode laser is well absorbed by melanin. The wavelength of erbium lasers is 2780 nm to 2940 nm and the light energy of erbium lasers is well absorbed by water and hydroxyapatite.
Erbium lasers are known as hard-tissue lasers and diode lasers are known as soft-tissue lasers. The light energy of diode lasers is well absorbed by pigmented tissue so a diode laser is a very effective tool in soft-tissue procedures such as frenctomy, gingivectomy, or biopsy. In addition to pigment, oral soft tissue has a high water content so erbium lasers can be used to perform the same procedures as the diode laser. Enamel, bone, cementum, and dentin also contain water so that the erbium lasers can remove these hard-tissues as well.
I use both soft-tissue and hard-tissues lasers in my practice. I use the Lasersmile diode laser and the Waterlase MD, both by BIOLASE. I use both lasers for soft-tissue procedures such as gingival troughing in preparation for impressions for crown and bridge procedures, gingivectomy to access subgingival caries, frenectomy, and biopsy. I use the Waterlase MD to remove caries and bone.
In my next post, I will share some specific clinical procedures that I have accomplished using lasers as well as the specific energy settings of the lasers.
Cynthia Jetter, DMD, owns a private laser dentistry practice with her husband, Donald W. Jetter, DMD, in Voorhees, New Jersey.