Lasers are used to remove caries, disinfect root canal during endodontic therapy and even re-shape gums, biopsy or lesion removal. Lasers can be used to remove a small piece of tissue (called a biopsy) so that it can be examined and to relieve the pain of canker sores.
Lasers of various wavelengths find uses in various aspects of dentistry. Lasers available in dentistry which operate within the mid-infrared region (2780–2940 nm, equivalent wavenumbers 3597–3401 cm−1), have been investigated because of their ability to cause a “cavitation” effect.The interaction of near-infrared wavelengths (810–1064 nm) with host tissue is predominately through a photothermal effect. In view of their high penetration depth into dental tissue, their penetration into dentine is shown to reach >1000 μm through scattering and transmission along the dentinal tubules, which in turn act as “light guides”. Since NIR-laser photonic energy can be absorbed by chromophores such as melanin, only pigmented microorganisms will be susceptible to direct inactivation. Additionally, an indirect microbicidal effect will occur from photothermal damage.
Apart from ultrasonic irrigation techniques, laser use in endodontics has been a major field of research since their introduction in dentistry. Lasers have been investigated to address the risk of failure of endodontic therapy due to the complexity of the root canal system. Lasers have been used therapeutically, in direct irradiation of the root canals or adjunct to irrigants placed into the canals, in combination with a photosensitizer (antimicrobial photodynamic therapy) and in pain management (photobiomodulation). Laser use in endodontic therapy has further developed through antimicrobial photodynamic therapy and has been adopted as an adjunct alternative.