title: Surface roughness and morphologic changes of zirconia following different surface treatments.
abstract: OBJECTIVE
  The aim of this study was to evaluate the roughness and morphology of zirconia after air abrasion and erbium:yttrium-aluminum-garnet (Er:YAG) laser application of different intensities.
  
  
  BACKGROUND
  Although surface roughness is important to obtain micromechanical retention, it is unclear which surface treatment is most appropriate for zirconia.
  
  
  METHODS
  Fifty sintered zirconia specimens were divided into five groups (n=10). The following treatments were applied: control, Er:YAG laser irradiation with different energy intensities (200, 300, and 400 mJ), and air abrasion with aluminum oxide (Al(2)O(3)) particles (110 μm). Morphologic changes after surface treatments were examined in microscope analyses. Then, the surface roughness (Ra in μm) of the specimens was evaluated using a surface texture measuring instrument. Roughness data were analyzed using one-way analysis of variance (ANOVA) and Tukey's honestly significant difference (HSD) test (p=0.05).
  
  
  RESULTS
  Results of microscope analyses revealed changes in surface morphology after surface treatments, including the formation of rare pits in the 400 mJ laser group and the formation of microretentive grooves in the air abrasion group. According to the results of the statistical analysis, the mean surface roughness value for the air abrasion group was significantly higher than that of the other groups (p<0.001). Except for the air abrasion group, there were no statistically significant differences within other groups (p>0.05).
  
  
  CONCLUSIONS
  According to the results of the statistical and microscopic analyses, 400 mJ Er:YAG laser energy or air abrasion can be used to obtain micromechanical retention prior to luting; however, air abrasion is the most effective surface treatment method.
authors.affiliation: Department of Prosthodontics, Faculty of Dentistry, Selcuk University, Konya, Turkey. necladt@yahoo.com
authors.forename: Necla
authors.initials: N
authors.lastname: Demir
authors.forename: M Gülce
authors.initials: MG
authors.lastname: Subaşi
authors.forename: A Nilgun
authors.initials: AN
authors.lastname: Ozturk
mesh_terms: D020906:Air Abrasion, Dental / Q000379:methods*; D000537:Aluminum Oxide / Q000494:pharmacology; D000704:Analysis of Variance; D003775:Dental Polishing; D003776:Dental Porcelain; D003799:Dental Stress Analysis; D006801:Humans; D053844:Lasers, Solid-State / Q000627:therapeutic use*; D028022:Low-Level Light Therapy / Q000379:methods*; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D012016:Reference Values; D033081:Shear Strength; D013499:Surface Properties / Q000187:drug effects / Q000528:radiation effects; D015040:Zirconium / Q000528:radiation effects*
chemical_list: D003776:Dental Porcelain; D015040:Zirconium; D000537:Aluminum Oxide; C028541:zirconium oxide