title: Complexity of the relationships between the sintering-temperature-dependent grain size, airborne-particle abrasion, ageing and strength of 3Y-TZP ceramics.
abstract: OBJECTIVE
  This study was designed to explore the complex relationships between the sintering-temperature-dependent grain size, airborne-particle abrasion, ageing and strength of 3Y-TZP ceramics.
  
  
  METHODS
  Biomedical grade 3Y-TZP powder was used to fabricate 180 discs. Half of them were sintered at 1400°C for 2h and half at 1500°C for 2h. A total of 18 groups of 10 were formed and subjected to the fully crossed experimental protocol of airborne-particle abrasion with Al2O3 at 2.5bar (no abrasion, 50μm, 110μm) and accelerated ageing at 134°C (no ageing, 12h, 48h). The relative amount of monoclinic phase was determined with XRD. The biaxial flexural strength was measured and statistically analyzed using the three-way ANOVA followed by predetermined contrasts and Tukey's HSD test (α=0.05).
  
  
  RESULTS
  The low-temperature-sintered, fine-grained ceramic exhibited an excellent ageing resistance, while the high-temperature-sintered, coarse-grained ceramic experienced a higher surface strengthening and a substantially improved ageing resistance with respect to the airborne-particle abrasion. The overall performance of this material was superior.
  
  
  CONCLUSIONS
  Our results show that the sintering temperature has a minor effect on the flexural strength, but it plays a crucial role in the surface strengthening and the ageing behaviour of 3Y-TZP dental ceramics.
authors.affiliation: Department of Prosthodontics, Faculty of Medicine, University of Ljubljana, Hrvatski trg 6, SI-1000, Ljubljana, Slovenia. Electronic address: jasna.cotic@mf.uni-lj.si.
authors.forename: Jasna
authors.initials: J
authors.lastname: Cotič
authors.affiliation: Department of Prosthodontics, Faculty of Medicine, University of Ljubljana, Hrvatski trg 6, SI-1000, Ljubljana, Slovenia.
authors.forename: Peter
authors.initials: P
authors.lastname: Jevnikar
authors.affiliation: Engineering Ceramics Department, Jožef Stefan Institute, Jamova 39, SI-1000, Ljubljana, Slovenia.
authors.forename: Andraž
authors.initials: A
authors.lastname: Kocjan
authors.affiliation: Engineering Ceramics Department, Jožef Stefan Institute, Jamova 39, SI-1000, Ljubljana, Slovenia.
authors.forename: Tomaž
authors.initials: T
authors.lastname: Kosmač
mesh_terms: D020906:Air Abrasion, Dental; D003776:Dental Porcelain / Q000737:chemistry*; D003799:Dental Stress Analysis; D006358:Hot Temperature; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D010316:Particle Size; D018583:Pliability; D013499:Surface Properties; D015019:Yttrium / Q000737:chemistry*; D015040:Zirconium / Q000737:chemistry*
chemical_list: C499362:yttria stabilized tetragonal zirconia; D003776:Dental Porcelain; D015019:Yttrium; D015040:Zirconium
keywords: Airborne-particle abrasion; Grain size; Low-temperature degradation; Sintering temperature; Zirconia