Guest Editorial Lasers in Dentistry: Overview and Perspectives Tatjana Dostalova, MD, PhD, DrSc, MBA, 1 and Helena Jelinkova, MSc, PhD, DrSc 2 D ental treatment by laser radiation is nowadays a well-known and widely used technique in dentistry. The laser can be thought of as an alternative instrument that sometimes completes or substitutes for traditional dental techniques. Current applications of laser radiation in dentistry depend on the penetration depth of the radiation into the tissue (given by the radiation wavelength) and then on the duration of this interaction (continuous versus pulsed laser regime), on the energy, length of pulse, and radiation power. It is possible to summarize that for the purposes of current clinical dentistry, a span from the visible to the far infrared portions of the electromagnetic spectrum (*400 nm - 10.6 lm) can be used. The dental application can be divided on the following. Biostimulation and Healing Effect of Laser Radiation Low-level laser therapy is defined by specific characteristic parameters of the laser source, a value of power within the range of 10 - 3 –10 - 1 W, and a wavelength in the interval where the radiation is not absorbed by the water. Therefore, laser systems such as helium-neon, argon, and krypton, and mainly semiconductor laser diodes, including gallium arse- nide and gallium aluminum arsenide, can be used in this case. The main applications are wound healing after tooth extraction, temporomandibular joint rehabilitation, soft-tissue healing, herpes labialis, glossodynia, and angular cheilitis. Laser radiation directly influences healing stimulation and pain reduction. The anti-inflammatory, analgesic, and bios- timulative effects were also confirmed. 1,2 Lasers in Periodontal Procedures Lasers have the potential advantages of producing a bactericidal and detoxification effect, and also of removing the epithelium lining and granulation tissue, which are de- sirable properties for the treatment of periodontal pockets. 3 Some lasers may be capable of effective removal not only of dental plaque but also of calculus from the root surface. This causes extremely low mechanical stress, and, therefore, a smear layer is not formed on the treated root surface. 4 The Er:YAG laser is a useful tool for debriding safely and ef- fectively both the root surface and gingival tissue of the periodontal pockets, and the Nd:YAG, diode, and argon lasers have a potential for soft tissue curettage and disin- fection of periodontal pockets. The alexandrite and Er:YAG laser has also shown highly promising results for use in selective calculus removal. 3 Bone and Soft Tissue Laser Therapy The radiations of some lasers reduce bleeding intra- operatively and lead to the patient feeling less pain post- operatively. 5 Visible wavelengths generated by argon or KTP lasers are absorbed and scattered in the same proportion at the peak value of the hemoglobin absorption curve; therefore, these lasers have superficial penetration from 0.1 lm to 1mm, and very good hemostatic effect on treating vascular lesions (i.e., hemangiomas). The absorption in water is minimal. Such lasers as the semiconductor, Nd:YAG or Nd:YAP are commonly used for cutting, vaporization, and decontamination of soft tissue. The laser indications are: papilloma, fibroma, hemangioma, venous lake, cysts, ulcers, herpes labialis, epulis, pyogenic granuloma, gingivectomy, and frenectomy. 6 Laser radiation can also be of assistance in treating dental trauma. The Er:Cr:YSGG, Cr:Tm:Er:YAG, or Er:YAG lasers, and the far-infrared CO 2 provide more effi- cient ablation whenever healthy or minimally pigmented and vascularized tissue is treated. Treatment of Dentin Hypersensitivity by Laser Radiation Dentin hypersensitivity is characterized by short, sharp pain arising from exposed dentin as a response to stimuli typically thermal, evaporative, tactile, osmotic, or chemical, which cannot be ascribed to any other form of dental defect or pathology. The lasers used for treating dentin hypersensitivity are divided into two groups: low-level continual lasers (such as He-Ne or GaAlAs lasers), and lasers with higher power (Nd:YAG or CO 2 lasers). Low output power laser therapy has an anti-inflammatory effect and stimulates nerve cells. The mechanism of Nd:YAG and CO 2 laser is the narrowing of dentinal tubules as well as direct nerve analgesia. 7 Photoactivated Dye Disinfection Using Laser Radiation This technique is effective in killing bacteria in complex biofilms such as subgingival plaque and carious lesions, as visible red light transmits well across dentin. The photo- activated dye technique can be undertaken with a range of visible red and near infrared lasers and systems using low power (100 mW) He-Ne or visible red semiconductor diode 1 Second Medical Faculty, Department of Stomatology, Charles University, Prague, Czech Republic. 2 Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, Prague, Czech Republic. Photomedicine and Laser Surgery Volume 31, Number 4, 2013 ª Mary Ann Liebert, Inc. Pp. 147–149 DOI: 10.1089/pho.2013.3493 147