are needed in order to keep the tip of the scaler touching the surface of the tooth, while overlapping oblique, horizontal, or vertical strokes are used for adequate calculus removal. Current research on potentially more effective methods of subgingival calculus removal focuses on the use of near-ultraviolet and near-infrared lasers, such as Er,Cr:YSGG lasers. The use of lasers in periodontal therapy offers a unique clinical advantage over conventional hand instrumentation, as the thin and flexible fibers can deliver laser energy into periodontal pockets that are otherwise difficult to access. Near-infrared lasers, such as the Er,CR:YSGG laser, have been proposed as an effective adjunct for calculus removal as the emission wavelength is highly absorbed by water, a large component of calculus deposits. An optimal output power setting of 1.0-W with the near-infrared Er,Cr:YSGG laser has been shown to be effective for root scaling. Near-ultraviolet lasers have also shown promise as they allow the dental professional to remove calculus deposits quickly, without removing underlying healthy tooth structure, which often occurs during hand instrumentation. Additionally, near-ultraviolet lasers are effective at various irradiation angles for calculus removal. Discrepancies in the efficiency of removal are due to the physical and optical properties of the calculus deposits, not to the angle of laser use. Dental hygienists must receive additional theoretical and clinical training on the use of lasers, where legislation permits. See also Calculus (medicine) Toothbrush Tooth decay Teeth cleaning References Periodontal disorders Fouling