title: Fatigue resistance and failure mode of adhesively restored custom metal-composite resin premolar implant abutments.
abstract: OBJECTIVE
  To evaluate the fatigue resistance and failure mode of composite resin and porcelain onlays and crowns bonded to premolar custom metal-composite resin premolar implant abutments.
  
  
  METHODS
  Sixty composite resin mesostructures were fabricated with computer assistance with two preparation designs (crown vs onlay) and bonded to a metal implant abutment. Following insertion into an implant with a tapered abutment interface (Titamax CM), each metal-composite resin abutment was restored with either composite resin (Paradigm MZ100) or ceramic (Paradigm C) (n = 15) and attached with adhesive resin (Optibond FL) and a preheated light-curing composite resin (Filtek Z100). Cyclic isometric chewing (5 Hz) was then simulated, starting with 5,000 cycles at a load of 50 N, followed by stages of 200, 400, 600, 800, 1,000, 1,200, and 1,400 N (25,000 cycles each). Samples were loaded until fracture or to a maximum of 180,000 cycles. The four groups were compared using life table survival analysis (log-rank test). Previously published data using zirconia abutments of the same design were included for comparison.
  
  
  RESULTS
  Paradigm C and MZ100 specimens fractured at average loads of 1,133 N and 1,266 N, respectively. Survival rates ranged from 20% to 33.3% (ceramic crowns and onlays) to 60% (composite resin crowns and onlays) and were significantly different (pooled data for restorative material). There were no restoration failures, but there were adhesive failures at the connection between the abutment and the mesostructure. The survival of the metal-composite resin premolar abutments was inferior to that of identical zirconia abutments from a previous study (pooled data for abutment material).
  
  
  CONCLUSIONS
  Composite resin onlays/crowns bonded to metal-composite resin premolar implant abutments presented higher survival rates than comparable ceramic onlays/crowns. Zirconia abutments outperformed the metal-composite resin premolar abutments.
authors.forename: Luís Leonildo
authors.initials: LL
authors.lastname: Boff
authors.forename: Elisa
authors.initials: E
authors.lastname: Oderich
authors.forename: Antônio Carlos
authors.initials: AC
authors.lastname: Cardoso
authors.forename: Pascal
authors.initials: P
authors.lastname: Magne
mesh_terms: D000269:Adhesives / Q000009:adverse effects; D002516:Ceramics / Q000737:chemistry; D003442:Crowns; D000044:Dental Abutments / Q000009:adverse effects; D059605:Dental Implant-Abutment Design; D003764:Dental Materials / Q000737:chemistry*; D003776:Dental Porcelain / Q000737:chemistry*; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis; D008670:Metals / Q000737:chemistry; D008963:Molar; D012117:Resins, Synthetic / Q000737:chemistry*; D015040:Zirconium / Q000737:chemistry
chemical_list: D000269:Adhesives; D003764:Dental Materials; D008670:Metals; D012117:Resins, Synthetic; D003776:Dental Porcelain; D015040:Zirconium