title: Effect of zirconia surface treatment on zirconia/veneer interfacial toughness evaluated by fracture mechanics method.
abstract: OBJECTIVE
  The aim of this study was to evaluate the effect of the airborne-particle abrasion and liner application on the interfacial toughness between veneering porcelain and zirconia core by means of a fracture mechanics test.
  
  
  METHODS
  Beam-shaped zirconia specimens were sectioned and divided into 4 groups according to different surface treatments as follows: Group C (control): no treatment; Group L: application of liner; Group A: airborne-particle abrasion with Al2O3 (sandblasting); and Group AL: airborne-particle abrasion and application of liner. The zirconia surfaces before and after sandblasting were observed and analyzed by SEM and white light interferometer. Specimens of each pretreated group were veneered with 3 core/veneer thickness ratios of 2:3, 1:1, and 3:2, corresponding to 3 phase angles respectively. Fracture mechanics test was performed on each specimen, the energy release rate G and phase angle ψ were calculated to characterize interfacial toughness. The experimental data were analyzed statistically using three-way ANOVA and the Tukey's HSD test. The surfaces of fractured specimens were examined by SEM and EDX.
  
  
  RESULTS
  At each phase angle, the interfaces with no treatment had higher mean G values than that of other groups. All the specimens showed mixed failure mode with residual veneer or liner on the zirconia surfaces.
  
  
  CONCLUSIONS
  The toughness of zirconia/veneer interface with no treatment is significantly higher than that of interfaces subjected to liner application and airborne-particle abrasion.
  
  
  CONCLUSIONS
  Liner application and airborne-particle abrasion seem to reduce zirconia/veneer interfacial toughness. Therefore, the two surface treatment methods should be applied with caution.
authors.affiliation: Key Laboratory of High Efficiency and Clean Mechanical Manufacture (Ministry of Education), School of Mechanical Engineering, Shandong University, Jinan 250061, PR China.
authors.forename: Gaoqi
authors.initials: G
authors.lastname: Wang
authors.affiliation: Key Laboratory of High Efficiency and Clean Mechanical Manufacture (Ministry of Education), School of Mechanical Engineering, Shandong University, Jinan 250061, PR China. Electronic address: zhangsong@sdu.edu.cn.
authors.forename: Song
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Department of Prosthodontics, Qilu Hospital of Shandong University, Jinan 250012, PR China.
authors.forename: Cuirong
authors.initials: C
authors.lastname: Bian
authors.affiliation: Department of Prosthodontics, Qilu Hospital of Shandong University, Jinan 250012, PR China.
authors.forename: Hui
authors.initials: H
authors.lastname: Kong
mesh_terms: D000465:Algorithms; D000537:Aluminum Oxide / Q000737:chemistry; D002516:Ceramics / Q000737:chemistry*; D045662:Dental Etching / Q000379:methods; D003764:Dental Materials / Q000737:chemistry*; D003776:Dental Porcelain / Q000737:chemistry; D003799:Dental Stress Analysis / Q000295:instrumentation; D003801:Dental Veneers; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D007368:Interferometry / Q000379:methods; D008027:Light; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D013314:Stress, Mechanical; D013499:Surface Properties; D015019:Yttrium / Q000737:chemistry*; D015040:Zirconium / Q000737:chemistry*
chemical_list: D003764:Dental Materials; C499362:yttria stabilized tetragonal zirconia; D003776:Dental Porcelain; D015019:Yttrium; D015040:Zirconium; D000537:Aluminum Oxide
keywords: Airborne-particle abrasion; Bilayer; Interfacial toughness; Liner