title: Comparative evaluation of antimicrobial effects of Er:YAG, diode, and CO₂ lasers on titanium discs: an experimental study.
abstract: OBJECTIVE
  This study examined carbon dioxide (CO(2); 10,600 nm), diode (808 nm), and erbium (Er):yttrium-aluminum-garnet (YAG; 2,940 nm) laser applications on Staphylococcus aureus contaminated, sandblasted, large-grit, acid-etched surface titanium discs and performed a comparative evaluation of the obtained bactericidal effects and the applicability of these effects in clinical practice.
  
  
  METHODS
  This study was carried out in 5 main groups: Er:YAG laser in very short pulse (VSP) emission mode, Er:YAG laser in short pulse (SP) emission mode, diode laser with a 320-nm fiber optic diode laser with an R24-B handpiece, and CO(2) laser. After laser irradiation, dilutions were spread on sheep blood agar plates and, after an incubation period of 24 hours, colony-forming units were counted and compared with the control group, and the bactericidal activity was assessed in relation to the colony counts.
  
  
  RESULTS
  The CO(2) laser eliminated 100% of the bacteria at 6 W, 20 Hz, and a 10-ms exposure time/pulse with a 10-second application period (0.8-mm spot size). The continuous-wave diode laser eliminated 97% of the bacteria at 1 W using a 10-second application with a 320-μm optic fiber, 100% of the bacteria were killed with a 1-W, 10-second continuous-wave application with an R14-B handpiece. The Er:YAG laser eliminated 100% of the bacteria at 90 mJ and 10 Hz using a 10-second application in a superpulse mode (300-ms exposure time/pulse). The Er:YAG laser also eliminated 99% to 100% of the bacteria in VSP mode at 90 mJ and 10 Hz with a 10-second application.
  
  
  CONCLUSIONS
  The results of this study show that a complete, or near complete, elimination of surface bacteria on titanium surfaces can be accomplished in vitro using a CO(2), diode, or Er:YAG laser as long as appropriate parameters are used.
authors.affiliation: Faculty of Dentistry, Department of Oral and Maxillofacial Surgery, Blacksea Technical University, Trabzon, Turkey. emretosun1980@gmail.com
authors.forename: Emre
authors.initials: E
authors.lastname: Tosun
authors.forename: Ferda
authors.initials: F
authors.lastname: Tasar
authors.forename: Robert
authors.initials: R
authors.lastname: Strauss
authors.forename: Dolunay Gulmez
authors.initials: DG
authors.lastname: Kıvanc
authors.forename: Cem
authors.initials: C
authors.lastname: Ungor
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D058491:Bacterial Load / Q000528:radiation effects; D001431:Bacteriological Techniques; D003666:Decontamination / Q000379:methods; D045662:Dental Etching / Q000379:methods; D003764:Dental Materials / Q000528:radiation effects*; D006801:Humans; D054020:Lasers, Gas / Q000627:therapeutic use*; D054023:Lasers, Semiconductor / Q000627:therapeutic use*; D053844:Lasers, Solid-State / Q000627:therapeutic use*; D008422:Materials Testing; D055100:Optical Fibers; D011829:Radiation Dosage; D013211:Staphylococcus aureus / Q000528:radiation effects*; D013499:Surface Properties; D013997:Time Factors; D014025:Titanium / Q000528:radiation effects*
chemical_list: D003764:Dental Materials; D014025:Titanium