title: Fatigue resistance and failure mode of adhesively restored custom implant zirconia abutments.
abstract: OBJECTIVE
  This study assessed the fatigue resistance and failure mode of porcelain and composite resin crowns and onlays bonded to premolar custom zirconia implant abutments.
  
  
  METHODS
  Sixty standardized zirconia implant abutments were milled (NeoShape) according to two different restoration designs (onlay or crown). Using Cerec 3, the corresponding onlays and crowns were fabricated either in ceramic (Paradigm C) or composite resin (Paradigm MZ100), resulting in four experimental groups (n = 15). The fitting surfaces of the abutments were airborne-particle abraded and cleaned. The intaglio surfaces of the restorations were HF-etched and silanated (Paradigm C) or airborne-particle abraded and silanated (Paradigm MZ100). Following insertion of the abutments into a Morse taper implant (Titamax CM), all restorations were bonded with a zirconia primer (Z-Prime Plus), adhesive resin (Optibond FL), and a preheated light curing composite resin (Filtek Z100). Cyclic isometric chewing (5 Hz) was simulated, starting with a load of 50N (5000×), followed by stages of 200N, 400N, 600N, 800N, 1000N, 1200N, and 1400N (25,000× each). Samples were loaded until fracture or to a maximum of 180,000 cycles. The four groups were compared using the life table survival analysis (Logrank test at P = 0.05).
  
  
  RESULTS
  All composite resin onlays and crowns survived (100% survival rate), while ceramic ones fractured at an average load of 1347N and 1280N, respectively, (survival rate of 46.7% and 20%) with a significant difference in survival probability (P < 0.0001). Fractures consisted in partial or total failure of the restoration only (no abutment failure, no screw loosening).
  
  
  CONCLUSIONS
  Composite resin onlays and crowns bonded to custom zirconia implant abutments presented a significant higher survival rate when compared to ceramic onlays and crowns.
authors: Department of Restorative Sciences, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, CA 90089-7792, USA.
authors: Elisa
authors: E
authors: Oderich
authors: Luís Leonildo
authors: LL
authors: Boff
authors: Antônio Carlos
authors: AC
authors: Cardoso
authors: Pascal
authors: P
authors: Magne
mesh_terms: D000134:Acid Etching, Dental; D002516:Ceramics / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry*; D017076:Computer-Aided Design; D003442:Crowns; D000044:Dental Abutments; D001840:Dental Bonding; D003776:Dental Porcelain / Q000737:chemistry*; D017267:Dental Prosthesis Design; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis; D007284:Inlays; D019279:Resin Cements / Q000737:chemistry; D015040:Zirconium / Q000737:chemistry*
chemical_list: D003188:Composite Resins; C469607:OptiBond FL; D019279:Resin Cements; C452079:paradigm MZ100; D003776:Dental Porcelain; C074543:Cerec; D015040:Zirconium; C028541:zirconium oxide