title: Ablative potential of the erbium-doped yttrium aluminium garnet laser and conventional handpieces: a comparative study.
abstract: OBJECTIVE
  To compare the ability of the Variable Square Pulse technology (VSP-technology)-based erbium-doped yttrium aluminium garnet (Er:YAG) laser working in maximum speed (MAX) mode (1000 mJ, 300 micros, 20 Hz) and the high-speed handpiece to ablate enamel, to compare the ability of for the VSP-technology-based Er:YAG laser working in MAX mode and the low-speed handpiece to ablate dentin, and to analyze in vitro effects of Er:YAG ablation of enamel and dentine surfaces using scanning electron microscopy (SEM).
  
  
  BACKGROUND
  A VSP-technology-based Er:YAG laser operating in MAX mode should be appropriate for achieving the maximum ablating speed in hard dental tissues.
  
  
  METHODS
  The experiment was conducted on extracted, cleaned, sterilized human molar teeth. Cavity preparations were made in hard dental tissues using the VSP-technology Er:YAG laser in MAX mode, in enamel using the high-speed handpiece, and in dentin using the low-speed handpiece at different time intervals. A laser triangulation profilometer was used to determine cavity volumes. The cavity surfaces of five specimens were examined using SEM.
  
  
  RESULTS
  The Er:YAG laser removed a volume of enamel that was 3.3 times as large as that removed by the high-speed handpiece in the same period of time. In dentin, the Er:YAG laser removed 8 to 18 times as much volume as the steel bur in the same period of time. The Er:YAG ablation rate in dentin was faster than in enamel. SEM of laser prepared cavities showed a well-defined surface, free of the smear layer.
  
  
  CONCLUSIONS
  The VSP-technology-based Er:YAG laser, working in MAX mode, is more efficient than mechanical drills for enamel and dentin ablation.
authors.affiliation: Department of Endodontics and Restorative Dentistry, School of Dental Medicine, Zagreb, Croatia. baraba@sfzg.hr
authors.forename: Anja
authors.initials: A
authors.lastname: Baraba
authors.forename: Ivana
authors.initials: I
authors.lastname: Miletic
authors.forename: Silvana Jukic
authors.initials: SJ
authors.lastname: Krmek
authors.forename: Tadej
authors.initials: T
authors.lastname: Perhavec
authors.forename: Zelimir
authors.initials: Z
authors.lastname: Bozic
authors.forename: Ivica
authors.initials: I
authors.lastname: Anic
mesh_terms: D003737:Dental Cavity Preparation / Q000295:instrumentation / Q000379:methods*; D003743:Dental Enamel / Q000528:radiation effects* / Q000648:ultrastructure; D003754:Dental High-Speed Equipment; D006801:Humans; D053844:Lasers, Solid-State; D008855:Microscopy, Electron, Scanning; D008963:Molar; D018709:Statistics, Nonparametric; D013499:Surface Properties / Q000528:radiation effects