title: Load-bearing capacity of custom-made versus prefabricated commercially available zirconia abutments.
abstract: OBJECTIVE
  To compare the load-bearing capacity of custom-made zirconia abutments with that of prefabricated commercially available zirconia abutments.
  
  
  METHODS
  Zirconia (ICE Zircon) blocks were manually copy-milled to abutments using prefabricated commercially available abutments as models, divided into four groups (n = 10/group), and sintered at 1,500°C. Prefabricated commercially available abutments were used as controls (groups 1 and 4, n = 10/group). The abutments in the study groups were: (1) Astra ZirDesign (AstraTech); (2) copy-milled Zirkonzahn-Astra; (3) copy-milled Zirkonzahn-Astra, short; (4) Xive Cercon (Dentsply/Friadent); (5) copy-milled Zirkonzahn-Xive; and (6) copy-milled Zirkonzahn-Xive, modified. Seven abutments per group were screwed onto implant replicas (size 3.5/4.0 mm for AstraTech, 3.8 mm for Dentsply Friadent) with acrylic resin sample base; the implants were loaded dry with a universal testing machine at room temperature and a 45-degree loading angle. Statistical analyses were made using one-way analysis of variance. The three remaining abutments per group were screwed onto implant replicas, and the distance between the replica and the abutment was measured with a scanning electron microscope.
  
  
  RESULTS
  Significant differences were seen among the groups in terms of load-bearing capacity; copy-milled Zirkonzahn-Xive modified abutments (group 6) were statistically significantly stronger (1,099 N) than the other abutments (P < .05). The Xive models resulted in catastrophic failure, whereas the Astra-design revealed visual bending before failure.
  
  
  CONCLUSIONS
  Custom-made zirconia abutments have comparable failure loads to those seen for prefabricated commercially available zirconia abutments.
authors.affiliation: Department of Biomaterials Science, University of Turku, Turku, Finland. jenhje@utu.fi
authors.forename: Jenni
authors.initials: J
authors.lastname: Hjerppe
authors.forename: Lippo V J
authors.initials: LV
authors.lastname: Lassila
authors.forename: Tero
authors.initials: T
authors.lastname: Rakkolainen
authors.forename: Timo
authors.initials: T
authors.lastname: Narhi
authors.forename: Pekka K
authors.initials: PK
authors.lastname: Vallittu
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D000044:Dental Abutments; D018772:Dental Marginal Adaptation; D003776:Dental Porcelain / Q000737:chemistry*; D017267:Dental Prosthesis Design; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis / Q000295:instrumentation; D006358:Hot Temperature; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D016474:Weight-Bearing; D015019:Yttrium / Q000737:chemistry*; D015040:Zirconium / Q000737:chemistry*
chemical_list: D000180:Acrylic Resins; C499362:yttria stabilized tetragonal zirconia; D003776:Dental Porcelain; D015019:Yttrium; D015040:Zirconium