title: Evaluation of the surface roughness and morphologic features of Y-TZP ceramics after different surface treatments.
abstract: OBJECTIVE
  This study aimed to investigate the effect of different energy intensities of the Er:YAG laser and of air abrasion with Al(2)O(3) particles on the surface roughness and morphologic characteristics of yttrium-stabilized tetragonal zirconia (Y-TZP) ceramics.
  
  
  BACKGROUND
  Surface roughness enhances the micromechanical interlocking of luting agents to ceramic surfaces. However, the most appropriate surface treatment for Y-TZP ceramics has yet to be determined.
  
  
  METHODS
  Two Y-TZP materials were evaluated: Cercon Smart Ceramics and Procera Zirconia. Thirty plates from each ceramic material were randomly divided into five groups according to the surface treatment received (none [control], air abrasion, or irradiation with the Er:YAG laser at three different energy intensities [200, 400, or 600 mJ]). After the surface treatments, the ceramic plates were gold-coated and their surface roughness (Ra, microm) was measured using confocal microscopy. For each ceramic system, the surface roughness was analyzed through two-way ANOVA/Tukey's test, with a 5% significance level. Changes in the morphological characteristics of the ceramics were examined through light and scanning electron microscopy.
  
  
  RESULTS
  For both zirconia-based materials, irradiation with 400 mJ or 600 mJ increased surface roughness and provided significant morphological changes. Air-abraded Cercon surfaces were rougher compared to the ones irradiated with 200 mJ of laser energy, whereas Procera surfaces irradiated with 200 mJ were rougher than the air-abraded ones.
  
  
  CONCLUSIONS
  Higher laser power settings (400 and 600 mJ) cause excessive material deterioration, making them unsuitable as surface treatments for zirconia surfaces. Irradiation with 200 mJ provides mild surface alterations, with intermediary features between the effects of air abrasion and higher laser intensities.
authors.affiliation: Department of Restorative Dentistry, Piracicaba Dental School, UNICAMP, Piracicaba, São Paulo, Brazil. dea.cavalcanti@uol.com.br
authors.forename: Andrea N
authors.initials: AN
authors.lastname: Cavalcanti
authors.forename: Peter
authors.initials: P
authors.lastname: Pilecki
authors.forename: Richard Mark
authors.initials: RM
authors.lastname: Foxton
authors.forename: Timothy F
authors.initials: TF
authors.lastname: Watson
authors.forename: Marcelo Tavares
authors.initials: MT
authors.lastname: Oliveira
authors.forename: Marcelo
authors.initials: M
authors.lastname: Gianinni
authors.forename: Giselle M
authors.initials: GM
authors.lastname: Marchi
mesh_terms: D020906:Air Abrasion, Dental; D000537:Aluminum Oxide; D000704:Analysis of Variance; D003775:Dental Polishing; D003776:Dental Porcelain / Q000737:chemistry*; D003799:Dental Stress Analysis; D007834:Lasers; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D011897:Random Allocation; D013499:Surface Properties; D015019:Yttrium / Q000737:chemistry*; D015040:Zirconium
chemical_list: C499362:yttria stabilized tetragonal zirconia; D003776:Dental Porcelain; D015019:Yttrium; D015040:Zirconium; D000537:Aluminum Oxide