title: Surface roughness and morphologic changes of zirconia: effect of different surface treatment.
abstract: OBJECTIVE
  The purpose of this study was to investigate the surface roughness and morphologic changes of pre-sintered ZrO 2 after sandblasting and erbium, chromium: Yttrium, scandium, gallium, garnet (Er, Cr: YSGG) laser application of different intensities.
  
  
  METHODS
  Eighty pre-sintered ZrO 2 cylinders (7 mm diameter, 3 mm height) were prepared and divided into eight groups. Specimens in the control group were not treated. The following treatments were applied: Er, Cr: YSGG laser irradiation with different energy intensities (1-6 W at 20 Hz, with air-water cooling proportion of 65%/55%) and air abrasion with Al 2 O 3 particles (120 μm). Then, all the specimens were sintered. The average surface roughness of each specimen was determined with a profilometer, and the morphology changes of a specimen from each group were evaluated with scanning electron microscope (SEM) analyses. The surface roughness data were analyzed through one-way analysis of variance and Tukey's honestly significant difference test (P < 0.05).
  
  
  RESULTS
  There were significant differences between 2 and 6 W irradiations and control group. The highest surface roughness value was obtained with 6 W irradiation (8.14 ± 1.26 Ra), followed by the 5 W (7.60 ± 1.12 Ra), 4 W (7.50 ± 0.90 Ra), 3 W (5.86 ± 1.03 Ra), 2 W (4.54 ± 0.53 Ra) and sandblasting group (2.18 ± 0.92 Ra). 1 W laser irradiation (0.80 ± 0.06 Ra) presented Ra values similar to the control group (0.77 ± 0.03).
  
  
  CONCLUSIONS
  The result of the statistical analyses and SEM images showed that Er, Cr: YSGG laser irradiation with 4-6 W/20 Hz presented significantly effect in surface roughness changes of zirconia than other surface treatments.
authors.affiliation: Department of Prosthodontics, Faculty of Dentistry, Akdeniz University, Antalya, Turkey.
authors.forename: O
authors.initials: O
authors.lastname: Kirmali
authors.forename: A
authors.initials: A
authors.lastname: Kustarci
authors.forename: A
authors.initials: A
authors.lastname: Kapdan
mesh_terms: D003764:Dental Materials; D006801:Humans; D053844:Lasers, Solid-State; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D013499:Surface Properties; D015040:Zirconium
chemical_list: D003764:Dental Materials; D015040:Zirconium; C028541:zirconium oxide