title: Surface Treatment by Different Parameters of Erbium:Yttrium-Aluminum-Garnet (Er:YAG) Laser: Scanning Electron Microscope (SEM) Evaluation.
abstract: BACKGROUND
  This study aimed to assess the Scanning Electron Microscope (SEM) analysis of tooth surface irradiated by erbium:yttrium-aluminum-garnet (Er:YAG) laser with various parameters.
  
  
  METHODS
  Number of 25 extracted human third molars free of caries were used in this study. The teeth were put into 5 groups for laser irradiation as follows: group 1 (power: 0.5 W, Energy: 50 mJ); group 2 (power: 1 W, Energy: 100 mJ); group 3 (power: 1.5 W, Energy: 150 mJ); group 4 (power: 2 W, Energy: 200 mJ); group 5 (power: 2.5 W, Energy: 250 mJ). All samples were prepared by repetition rate of 10 Hz and duration of 230 μs, using a non-contact handpiece at a distance of 4 mm. Then, the samples were prepared for SEM examination.
  
  
  RESULTS
  SEM evaluation of every 25 samples, treated by Er:YAG, showed that all groups had exposed dentinal tubules without any melted area or cracks.
  
  
  CONCLUSIONS
  In this study we used SEM to investigate ablated dentine with different parameters of Er:YAG laser energy. Our findings support these conclusions. All powers of laser below 3 W are proper for ablation, and make no cracks.
authors.affiliation: Laser Research Center of Dentistry (LRCD), Dental Research Institute, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Nasim
authors.initials: N
authors.lastname: Chiniforush
authors.affiliation: Laser Research Center of Dentistry (LRCD), Dental Research Institute, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Hanieh
authors.initials: H
authors.lastname: Nokhbatolfoghahaei
authors.affiliation: Department of Dental Prosthesis and Implants, Laser Research Center of Dentistry, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Abbas
authors.initials: A
authors.lastname: Monzavi
authors.affiliation: Laser Research Center of Dentistry (LRCD), Dental Research Institute, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Edris
authors.initials: E
authors.lastname: Pordel
authors.affiliation: Department of Periodontics and Oral Medicine, Michigan School of Dentistry, MI, USA.
authors.forename: Sajjad
authors.initials: S
authors.lastname: Ashnagar
keywords: Dentinal tubules; Er:YAG; Laser; Scanning electron microscopy