Lasers in Dentistry: Minimally Invasive Instruments for the Modern Practice
Glossary

ablation – The process of removing tissue with a laser through vaporization or mechanical disruption.

absorption – Specific molecules in the tissue known as chromophores absorb the photons.  The light energy is then converted into other forms of energy to perform work.

active medium – The laser component that actually produces laser light when stimulated.  Dental lasers use crystals, gas, or semiconductors as their active media.

beam transfer hardware – Mirrors, optical fibers, or hollow wave guide hardware that caries the laser beam from the machine to the handpiece.

chromophore – The tissue component that absorbs the laser energy and converts it into thermal energy.

coherence – The tendency of laser light waves to travel with their peaks and valleys in unison.

continuous wave mode – A form of laser emission when the laser is on continuously.

divergence – The tendency of the laser beam to spread outward once it exits the handpiece.  Divergence varies depending on the specific laser and hardware used.

energy density – The amount of laser energy in an area of exposed tissue.

Er,Cr:YSGG – Erbium, Chromium - doped Yttrium Scandium Gallium Garnet crystal.

Er:YAG – Erbium-doped Yttrium Aluminium Garnet crystal.

free running pulsed mode – A form of laser emission where laser light is emitted in discrete pulses with specific, measurable temporal characteristics.

gated wave mode – A form of laser emission where the beam is blocked part of the time by a shutter device creating a pulsed laser emission.

laser – Light Amplification by Stimulated Emission of Radiation.

millijoule – Measurement of energy.

monochromatic – In laser science refers specifically to the fact that lasers produce a single wavelength of light.

Nd:YAG – Neodymium-doped Yttrium Aluminium Garnet crystal.

optical pumping – Flash lamp stimulation of an active medium.

output coupler – A semi-transparent mirror in the resonator that the laser beam passes through into the beam transfer hardware.

photobiomodulation – The process whereby laser energy is used to stimulate positive clinical outcomes such as pain relief and improved healing.

power – Rate of doing work, measured in Watts.

pulse duration – The amount of time a laser pulse is on, measured in microseconds.

reflection – When the laser beam bounces off the surface with no penetration or interaction at all.

resonator – The mirrored chamber surrounding the active medium that helps to amplify the laser light produced.

scattering – The tendency of laser light to bounce in multiple directions once it enters tissue.

stimulated emission – The process whereby the active medium is stimulated by an external source of light or electricity to produce laser light.

thermal relaxation – The ability of tissue to absorb and dissipate heat produced by pulsed dental lasers.

transmission – When laser energy can pass through superficial tissues to interact with deeper areas.

watt – Power measurement of energy produced over time.