title: Influence of zirconia surface treatment on veneering porcelain shear bond strength after cyclic loading.
abstract: BACKGROUND
  The influence of yttria-stabilized tetragonal zirconia polycrystal surface treatment on veneering porcelain shear bond strength after cyclic loading is not fully understood.
  
  
  OBJECTIVE
  The purpose of this study was to investigate the influence of yttria-stabilized tetragonal zirconia polycrystal surface treatment on veneering porcelain shear bond strength and cyclic loading on the shear bond strength between the 2 materials.
  
  
  METHODS
  A total of 48 cylinder-shaped yttria-stabilized tetragonal zirconia polycrystal specimens were fabricated with computer-aided design and computer-aided manufacturing (CAD/CAM), sintered for 8 hours at 1500°C, ground with 320-grit diamond paper, and divided into 4 groups (n = 12) according to surface treatment as follows: no treatment/control; heat treatment of 650°C to 1000°C at 55°C/min; airborne-particle abrasion with 50-μm alumina at 0.4 MPa pressure for 10 seconds; or heat treatment after abrasion. A veneering porcelain cylinder was built and fired on the prepared yttria-stabilized tetragonal zirconia polycrystal specimens. The shear bond strength was tested with a universal testing machine. Six specimens from each group were subjected to cyclic loading (10000 cycles, 1.5 Hz, 10 N load) before testing.
  
  
  RESULTS
  The mean ± SD ranged from 10.7 ± 15.4 to 34.1 ± 10.0. Three-way ANOVA found no statistically significant (P > .05) effect of surface treatment and cyclic loading on shear bond strength. The Sidak multiple comparisons procedure found that cyclic loading specimens had significantly lower shear bond strength than noncyclic loading specimens after airborne-particle abrasion without heat treatment (P = .013).
  
  
  CONCLUSIONS
  Within the limitations of this study, the shear bond strength between yttria-stabilized tetragonal zirconia polycrystal and veneering porcelain was not significantly affected by surface treatment. Airborne-particle abrasion without subsequent heat treatment should be avoided as a surface treatment in fabrication methods.
authors.affiliation: Resident, Department of Restorative Dentistry, Indiana University School of Dentistry, Indianapolis, Ind.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Nishigori
authors.affiliation: Visiting Assistant Professor, Department of Restorative Dentistry, Indiana University School of Dentistry, Indianapolis, Ind.
authors.forename: Takamitsu
authors.initials: T
authors.lastname: Yoshida
authors.affiliation: Assistant Professor, Department of Restorative Dentistry, Indiana University School of Dentistry, Indianapolis, Ind.
authors.forename: Marco C
authors.initials: MC
authors.lastname: Bottino
authors.affiliation: Associate Professor, Department of Restorative Dentistry, Indiana University School of Dentistry, Indianapolis, Ind. Electronic address: jplatt2@iu.edu.
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Platt
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry; D002516:Ceramics / Q000737:chemistry*; D017076:Computer-Aided Design; D001840:Dental Bonding; D045662:Dental Etching / Q000379:methods; D003764:Dental Materials / Q000737:chemistry*; D003775:Dental Polishing / Q000295:instrumentation; D003776:Dental Porcelain / Q000737:chemistry*; D003799:Dental Stress Analysis / Q000295:instrumentation; D003801:Dental Veneers; D018130:Diamond / Q000737:chemistry; D006358:Hot Temperature; D006801:Humans; D008422:Materials Testing; D011312:Pressure; D033081:Shear Strength; D013314:Stress, Mechanical; D013499:Surface Properties; D013997:Time Factors; D015019:Yttrium / Q000737:chemistry*; D015040:Zirconium / Q000737:chemistry*
chemical_list: D003764:Dental Materials; C499362:yttria stabilized tetragonal zirconia; D003776:Dental Porcelain; D015019:Yttrium; D018130:Diamond; D015040:Zirconium; D000537:Aluminum Oxide