title: Fracture strength of monolithic all-ceramic crowns made of high translucent yttrium oxide-stabilized zirconium dioxide compared to porcelain-veneered crowns and lithium disilicate crowns.
abstract: OBJECTIVE
  The aim of the study was to provide data on the fracture strength of monolithic high translucent Y-TZP crowns and porcelain-veneered high translucent Y-TZP crown cores and to compare that data with the fracture strength of porcelain-veneered Y-TZP crown cores and monolithic lithium disilicate glass-ceramic crowns.
  
  
  METHODS
  Sixty standardized crowns divided into six groups (n = 10) were fabricated: monolithic high translucent Y-TZP crowns, brand A, monolithic high translucent Y-TZP crowns, brand B, veneered high translucent Y-TZP crown cores, brand A, veneered high translucent Y-TZP crown cores, brand B, heat-pressed monolithic lithium disilicate crowns and veneered Y-TZP crown cores. All crowns were thermocycled, cemented onto dies, cyclically pre-loaded and finally loaded to fracture.
  
  
  RESULTS
  The monolithic Y-TZP groups showed significantly higher fracture strength (2795 N and 3038 N) compared to all other groups. The fracture strength in the veneered Y-TZP group (2229 N) was significantly higher than the monolithic lithium disilicate group (1856 N) and the veneered high translucent Y-TZP groups (1480 N and 1808 N).
  
  
  CONCLUSIONS
  The fracture strength of monolithic high translucent Y-TZP crowns is considerably higher than that of porcelain-veneered Y-TZP crown cores, porcelain-veneered high translucent Y-TZP crown cores and monolithic lithium disilicate crowns. The fracture strength of a crown made of monolithic high translucent Y-TZP is, with a large safety margin, sufficient for clinical use for the majority of patients. Porcelain-veneered Y-TZP crown cores show higher fracture resistance than monolithic lithium disilicate crowns.
authors.affiliation: Department of Materials Science and Technology, Faculty of Odontology, Malmö University , Malmö , Sweden.
authors.forename: Camilla
authors.initials: C
authors.lastname: Johansson
authors.forename: Gratiela
authors.initials: G
authors.lastname: Kmet
authors.forename: Johnny
authors.initials: J
authors.lastname: Rivera
authors.forename: Christel
authors.initials: C
authors.lastname: Larsson
authors.forename: Per
authors.initials: P
authors.lastname: Vult Von Steyern
mesh_terms: D002516:Ceramics; D003442:Crowns; D003776:Dental Porcelain; D006801:Humans; D008422:Materials Testing; D015019:Yttrium; D015040:Zirconium
chemical_list: C493120:lithia disilicate; D003776:Dental Porcelain; D015019:Yttrium; D015040:Zirconium; C028541:zirconium oxide; C091417:yttria