title: Fracture resistance and failure location of zirconium and metallic implant abutments.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the fracture resistance and failure location of single-tooth, implant-supported, all-ceramic restorations on different implant abutments subjected to a maximum load.
  
  
  METHODS
  Forty Certain 3i implants and 20 ITI Straumann implants were used in this study in combination with 20 UCLA abutments, 20 ZiReal abutments, and 20 synOcta Ceramic Blanks to form three groups according to abutment type. All 60 abutments were prepared with standard measurements: a 1.0 mm deep chamfer, 2.0 mm of incisal reduction, and a total height of 7 mm. Sixty IPS Empress 2 full ceramic crowns were fabricated and cemented on each abutment with a resin cement. Static loading was simulated under maximum loading and fracture locations were noted.
  
  
  RESULTS
  The mean load to failure data and standard deviations for the three groups were as follows: Group 1 (792.7 N +/- 122.5) and Group 3 (793.6 +/- 162.3) showed no significant difference in fracture resistance while the values for specimens in Group 2 (604 N +/- 191.1) had the lowest mean value and were significantly lower. In Group 1, 16 crowns and four abutment fractures were reported, while in Group 3, 17 crowns and three abutments fractured. Group 2 actually showed three types of fractures. Two specimen fractures were located at the implant level, six with fractures occuring within the Empress 2 all-ceramic crown, and the remaining 12 failures were located at the abutment level.
  
  
  CONCLUSIONS
  Within the limitations of this laboratory study, the following conclusions were drawn: The mean load-to-failure values for all three groups were well above the reported normal maximal incisal load range. The load to failure for both the zirconium oxide (ZrO2) abutments (ZiReal on 3i Certain implants and synOcta Ceramic Blanks on SLA ITI Straumann implants) had mean fracture loads of 792.7 N (+122.6) and 604.2 N (+191.2), respectively. The zirconium oxide (ZrO2) ZiReal and titanium (UCLA) abutments on the 3i Certain implants had statistically significantly higher fracture loads (792.7 N and 703.7 N, respectively) than those recorded for the 3i Ceramic Blank abutments on the SLA ITI Straumann implant (604.2 N). The ITI Straumann Ceramic Blank abutments showed uniform fracture behavior. Fracture mainly emanated from the cervical buccal aspect of the abutment.
  
  
  CONCLUSIONS
  The three abutments tested showed they can withstand clinical loads above the normal range of mastication.
authors.affiliation: Department of Fixed Prosthodontics and Occlusion at Saint-Joseph University in Beirut, Lebanon. philippearamouni@gmail.com
authors.forename: Philippe
authors.initials: P
authors.lastname: Aramouni
authors.forename: Elie
authors.initials: E
authors.lastname: Zebouni
authors.forename: Esam
authors.initials: E
authors.lastname: Tashkandi
authors.forename: Salam
authors.initials: S
authors.lastname: Dib
authors.forename: Ziad
authors.initials: Z
authors.lastname: Salameh
authors.forename: Khalid
authors.initials: K
authors.lastname: Almas
mesh_terms: D003442:Crowns; D000044:Dental Abutments; D019250:Dental Implants, Single-Tooth; D003776:Dental Porcelain; D019094:Dental Prosthesis, Implant-Supported; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis; D006047:Gold Alloys; D008422:Materials Testing; D016876:Metal Ceramic Alloys; D014025:Titanium; D015040:Zirconium
chemical_list: D006047:Gold Alloys; C096534:Lodestar Gold Ceramic Alloy; D016876:Metal Ceramic Alloys; D003776:Dental Porcelain; D015040:Zirconium; D014025:Titanium