title: Load-to-fracture value of different all-ceramic crown systems.
abstract: OBJECTIVE
  The purpose was to investigate the potential difference in the load-to-fracture values of several all-ceramic crown systems. Five different coping-reinforced all-ceramic crown systems were selected. Ten crowns from each system were fabricated and luted to standardized titanium dies.
  
  
  METHODS
  The study consisted of five groups of ten samples each, all luted using G.C. Link Max resin adhesive cement. Group A: IPS Eris, Group B: Cerac In-lab Alumina coping, Group C: Cerac In-lab Zirconia coping, Group D: Procera AllCeram Alumina coping, and Group E: Procera Zirconia coping. Following cementation, the samples were placed under a 5 Kg static load for 10 minutes insuring proper seating and stored in 100% humidity for one week. All samples were visually inspected prior to testing and were loaded to fracture at the rate of 0.5 mm/min using a universal-testing machine.
  
  
  RESULTS
  Group A = 321.49 KgF +/- 113.69 (S.D.), Group B = 288.63 +/- 102.82 (S.D.), Group C = 266.58 +/- 69.17 (S.D.), Group D = 295.49 +/- 80.54 (S.D.), and Group E = 420.37 +/- 82.45 (S.D.). The data were analyzed using an unpaired t-test; this indicated a statistical difference between group E and all of the others (P-value =0.039).
  
  
  CONCLUSIONS
  We concluded under these conditions, the Procera Zirconia crown system has significant higher load-to-fracture value than several other all-ceramic crown systems.
authors.affiliation: Department of Restorative Dentistry, School of Dentistry, University of Michigan, Ann Arbor, MI, USA. mdsnyder@umich.edu
authors.forename: Mark David
authors.initials: MD
authors.lastname: Snyder
authors.forename: Kyle Douglas
authors.initials: KD
authors.lastname: Hogg
mesh_terms: D000537:Aluminum Oxide; D002516:Ceramics; D003188:Composite Resins; D003442:Crowns; D001840:Dental Bonding; D003776:Dental Porcelain; D017267:Dental Prosthesis Design; D003799:Dental Stress Analysis; D008422:Materials Testing; D019279:Resin Cements; D015040:Zirconium
chemical_list: D003188:Composite Resins; C500744:Eris ceramic; C470486:Linkmax; D019279:Resin Cements; C493120:lithia disilicate; D003776:Dental Porcelain; D015040:Zirconium; D000537:Aluminum Oxide; C028541:zirconium oxide