A laser is defined as a nondivergent, man-made, monochromatic, electromagnetic energy of one wavelength. It is a single color of light (monochromatic). Laser light is produced when an atom becomes excited, thus emitting a photon which is the elementary particle responsible for electromagnetic phenomena. The photon, as we learned in radiology class, is the carrier of electromagnetic radiation of all wavelengths. This photon then produces the coherent, focused, concentrated ray of light.
A laser’s effect in the mouth is dependent on three things: a laser’s wavelength, where the laser light falls on the light spectrum, and the target tissue with which the laser interacts.
Wavelength — This is the only parameter the practitioner cannot adjust on their lasers. Lasers come in many different wavelengths, and those wavelengths are generally measured in nanometers (nm). Wavelengths are absorbed by the tissue at varying degrees, which will correlate to the laser’s depth of penetration, and therefore determines its overall accuracy and precision in the mouth.12 Generally speaking, for most soft tissue procedures, the wavelengths used by dental hygienists range from 800 to 2,940 nm. For example, diode lasers, which are the most commonly used lasers by RDHs, come in either 810 nm, 910 nm, or 980 nm wavelengths.
Light spectrum — In addition to wavelength, where a laser falls on the light spectrum will greatly influence its properties. Most dental lasers fall into the infrared zone, which is just to the left of visible light. Some are deep into the infrared zone and others are closer to the junction of visible light (see Figure 1).
Hard Tissue Lasers
- Er:YAG Erbium-doped Yttrium Aluminum Garnet
- Er,Cr:YSGG Erbium, Chromium doped Yttrium Scandium Gallium Garnet
Soft Tissue Lasers
- Diode: AlGaAs Aluminum Gallium Arsenide 810 nm
- Diode: InGaAs Indium Gallium Arsenide 940-980 nm
- Nd:YAG Neodymium-doped Yttrium Aluminum Garnet
- Nd:YAP Neodymium-doped Yttrium Aluminum Perovskite
- CO2 Carbon dioxide