title: Evaluation of roughness, wettability, and morphology of an yttria-stabilized tetragonal zirconia polycrystal ceramic after different airborne-particle abrasion protocols.
abstract: BACKGROUND
  Airborne-particle abrasion is an effective method of roughening a zirconia surface and promoting micromechanical interlocks with luting cements. However, the effect of different airborne-particle abrasion protocols on the micromechanical retention mechanism has been poorly investigated.
  
  
  OBJECTIVE
  The purpose of the study was to evaluate the effect of airborne-particle abrasion protocols on the surface roughness, wettability, and morphology of an yttria-stabilized tetragonal zirconia polycrystal ceramic.
  
  
  METHODS
  A total of 140 zirconia specimens (14 × 14 × 1.4 mm) were made from Lava and divided into 7 groups. Their surfaces were treated as follows (n = 20): as-sintered (control); airborne-particle abraded with 50-μm Al2O3 particles; 120-μm Al2O3 particles; 250-μm Al2O3 particles; 30-μm silica-coated Al2O3 particles (Rocatec Soft); 110-μm silica-coated Al2O3 particles (Rocatec Plus); and 120-μm Al2O3 particles followed by Rocatec Plus. The surface roughness (Ra) and wettability analyses were performed on the same specimens of each group. The test liquid used for the wettability analysis was the silane RelyX Ceramic Primer. Two additional specimens (6.0 × 6.0 × 1.0 mm) per group were prepared to evaluate the surface morphology with scanning electron microscopy. The roughness (Ra) data were analyzed by 1-way ANOVA and the Dunnett C test (α = .05), and the wettability data with 1-way ANOVA (α = .05). The Spearman correlation analysis was applied to test for a possible correlation between roughness and wettability.
  
  
  RESULTS
  The control group (0.35 μm) exhibited the lowest mean roughness value (Ra), which was followed by Rocatec Soft (0.40 μm), 50-μm Al2O3 particles (0.52 μm), Rocatec Plus (0.69 μm), 120-μm Al2O3 particles (0.80 μm)/120-μm Al2O3 particles + Rocatec Plus (0.79 μm), and 250-μm Al2O3 particles (1.13 μm). No significant difference was found among the groups concerning wettability. No correlation (rs = -0.09; P = .27) was found between the 2 dependent variables. The scanning electron microscopy analysis indicated that the different airborne-particle abrasion protocols produced differences in the morphologic patterns.
  
  
  CONCLUSIONS
  Although roughness and morphology of the zirconia surface varied according to the airborne-particle abrasion protocol, no close relationship was found between them. The roughness increase seemed to have followed the size of the particles.
authors.affiliation: Adjunct Professor, Department of Dental Materials and Prosthodontics, Araraquara Dental School, Univ Estadual Paulista (UNESP), Araraquara, São Paulo, Brazil.
authors.forename: Filipe Oliveira
authors.initials: FO
authors.lastname: Abi-Rached
authors.affiliation: Postgraduate student, Department of Dental Materials and Prosthodontics, Araraquara Dental School, Univ Estadual Paulista (UNESP), Araraquara, São Paulo, Brazil.
authors.forename: Samira Branco
authors.initials: SB
authors.lastname: Martins
authors.affiliation: Associate Professor, Department of Social Dentistry, Araraquara Dental School, Univ Estadual Paulista (UNESP), Araraquara, São Paulo, Brazil.
authors.forename: Juliana Alvares
authors.initials: JA
authors.lastname: Campos
authors.affiliation: Associate Professor, Department of Dental Materials and Prosthodontics, Araraquara Dental School, Univ Estadual Paulista (UNESP), Araraquara, São Paulo, Brazil. Electronic address: renata@foar.unesp.br.
authors.forename: Renata Garcia
authors.initials: RG
authors.lastname: Fonseca
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry; D002516:Ceramics / Q000737:chemistry*; D020099:Coated Materials, Biocompatible / Q000737:chemistry; D045662:Dental Etching / Q000379:methods*; D003764:Dental Materials / Q000737:chemistry*; D006358:Hot Temperature; D006801:Humans; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D010316:Particle Size; D012821:Silanes / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D013499:Surface Properties; D013997:Time Factors; D017155:Wettability; D015019:Yttrium / Q000737:chemistry*; D015040:Zirconium / Q000737:chemistry*
chemical_list: D020099:Coated Materials, Biocompatible; D003764:Dental Materials; D008689:Methacrylates; D012821:Silanes; C499362:yttria stabilized tetragonal zirconia; C017492:methacryloxypropyltrimethoxysilane; D015019:Yttrium; D012822:Silicon Dioxide; D015040:Zirconium; D000537:Aluminum Oxide