Current applications of lasers in endodontics

The use of lasers within the scope of endodontic practice and research has increased significantly in the past few years. Lasers are generally classified according to their physical constructions and special wavelengths, which have impacts on their enhanced clinical usage. Lasers according to their physical constructions are divided into three groups. The first type is the solid state laser, so named because the medium, undergoing lasing, is in a solid form. Ruby laser is the prototype of all solid state lasers. By forming crystalline materials that are doped with rare earth elements a wide range of solid state lasers can be produced. Some of the most common types of solid state lasers use the YAG (Yttrium Aluminium Garnet) crystal (Holmium:YAG, Thulium:YAG Neodymium:YAG and Erbium:YAG) and the YSGG (Yttrium Scandium Gallium Garnet) crystal (Er,Cr:YSGG) as their base. The second major family of lasers are the gas lasers. In this group the lasing material that is ionized can be Argon gas, Carbon dioxide gas, Nitrogen gas or a Helium-Neon (He:Ne) gas mixture. The third family of lasers are the Diode lasers, which produce wavelengths in the visible spectrum. The most frequently used lasers in endodontics are: Neodymium:YAG (Nd:YAG), Diode Laser, Erbium:YAG (Er:YAG), Erbium Chromium:YSGG (Er,Cr:YSGG) and He:Ne laser. This paper reviews the most common applications of lasers in endodontics that include Laser Doppler Flowmetry (LDF), treatment of dentinal hypersensitivity, pulpotomy and pulp capping and root canal disinfection through laser activated irrigation and photo-activated root canal disinfection (PAD).