title: Effects of different lasers and particle abrasion on surface characteristics of zirconia ceramics.
abstract: OBJECTIVE
  The aim of this study was to assess the surface of yttrium-stabilized tetragonal zirconia (Y-TZP) after surface treatment with lasers and airborne-particle abrasion.
  
  
  METHODS
  First, 77 samples of presintered zirconia blocks measuring 10 × 10 × 2 mm were made, sintered and polished. Then, they were randomly divided into 11 groups (n=7) and received surface treatments namely, Er:YAG laser irradiation with output power of 1.5, 2 and 2.5 W, Nd:YAG laser with output power of 1.5, 2 and 2.5 W, CO2 laser with output power of 3, 4 and 5 W, AL2O3 airborne-particle abrasion (50μ) and no treatment (controls). Following treatment, the parameters of surface roughness such as Ra, Rku and Rsk were evaluated using a digital profilometer and surface examination was done by SEM.
  
  
  RESULTS
  According to ANOVA and Tukey's test, the mean surface roughness (Ra) after Nd:YAG laser irradiation at 2 and 2.5 W was significantly higher than other groups. Roughness increased with increasing output power of Nd:YAG and CO2 lasers. Treated surfaces by Er:YAG laser and air abrasion showed similar surface roughness. SEM micrographs showed small microcracks in specimens irradiated with Nd:YAG and CO2 lasers.
  
  
  CONCLUSIONS
  Nd:YAG laser created a rough surface on the zirconia ceramic with many microcracks; therefore, its use is not recommended. Air abrasion method can be used with Er:YAG laser irradiation for the treatment of zirconia ceramic.
authors.affiliation: Assistant Professor, Department of Restorative Dentistry, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Sakineh
authors.initials: S
authors.lastname: Arami
authors.affiliation: Associate Professor, Department of Restorative Dentistry, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Masoume Hasani
authors.initials: MH
authors.lastname: Tabatabae
authors.affiliation: PhD candidate of laser dentistry, Laser Research Center of Dentistry, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Seyedeh Fatemeh
authors.initials: SF
authors.lastname: Namdar
authors.affiliation: Assistant Professor, Department of Restorative Dentistry, School of Dentistry, Birjand University of Medical Sciences, Birjand, Iran.
authors.forename: Nasim
authors.initials: N
authors.lastname: Chiniforush
keywords: Air Abrasion; Laser Treatment; Scanning Electron Microscopy; Zirconia