title: The impact of luting agents and stiffness of implant-abutments on marginal adaptation, chipping, and fracture resistance of zirconia crowns.
abstract: OBJECTIVE
  This in vitro study evaluated the impact of cements and implant analogs with different e-moduli on marginal adaptation, chipping, and the fracture resistance of zirconia crowns.
  
  
  METHODS
  80 crowns (Cercon, DeguDent) were manufactured for 40 polyoxymethylene (POM) and 40 titanium (Ti) one-piece implant analogs and divided into 10 groups: A, zinc oxide phosphate (Hoffmann׳s Cement, Richter&Hoffmann, Berlin, D); B, zinc oxide eugenol (Temp Bond, KerrHawe, Bioggio, CH); C, resin (Variolink II, Ivoclar-Vivadent, Schaan, FL); D, zinc oxide without eugenol (Temp Bond NE, KerrHawe, Bioggio, CH); E, glass ionomer (Ketac Cem, 3M ESPE, Seefeld, D). All samples were thermally mechanically loaded (1.2 × 10(6)× 50 N; 3000 × 5°C/55°C). Marginal adaptation was semiquantitatively evaluated before and after ageing with a scanning electron microscope. After ageing, intact samples underwent a fracture resistance test.
  
  
  RESULTS
  The best sealed margins before ageing were achieved with resin and zinc oxide cement and with resin after ageing. Zinc oxide samples showed the most discontinuously sealed margins after ageing and the difference between POM and Ti samples was significant only for zinc oxide. The numbers of samples failing during TCML were as follows: A(Ti - POM)=0-1; B(Ti - POM)=0-5; C(Ti - POM)=1/1; D(Ti - POM)=2-2; E (Ti - POM)=0-2. Fracture resistance test [N]: A(Ti - POM)=1181-801; B(Ti - POM)=1469-1517; C(Ti - POM)=1704-1408; D(Ti - POM)=1992-883; E (Ti - POM)=2750-1015.
  
  
  CONCLUSIONS
  TCML reduced the number of perfectly sealed samples and increased the number of chipped samples cemented onto POM implants with zinc oxide. This study could not show any significant impact on the fracture resistance of zirconia when different cements and implant analogs were used.
authors.affiliation: Department of Prosthetic Dentistry, Regensburg University Medical Center, Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany. Electronic address: lina.schaefer@ukr.de.
authors.forename: Lina
authors.initials: L
authors.lastname: Schäfer
authors.affiliation: Department of Cranio-Maxillo-Facial Surgery, Regensburg University Medical Center, Regensburg, Germany.
authors.forename: Cornelia
authors.initials: C
authors.lastname: Winkler
authors.affiliation: Private Practice, Dr. Jünger, Lam, Germany.
authors.forename: Genoveva
authors.initials: G
authors.lastname: Brandl
authors.affiliation: Department of Prosthetic Dentistry, Regensburg University Medical Center, Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Eckl
authors.affiliation: Department of Prosthetic Dentistry, Regensburg University Medical Center, Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany.
authors.forename: Verena
authors.initials: V
authors.lastname: Preis
authors.affiliation: Department of Prosthetic Dentistry, Regensburg University Medical Center, Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Behr
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D001672:Biocompatible Materials / Q000737:chemistry*; D002484:Cementation; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding; D003738:Dental Cements / Q000737:chemistry; D015921:Dental Implants; D017267:Dental Prosthesis Design; D003799:Dental Stress Analysis; D005899:Glass Ionomer Cements / Q000737:chemistry; D006801:Humans; D008277:Magnesium Oxide / Q000737:chemistry; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D011076:Polycarboxylate Cement / Q000737:chemistry; D011140:Polyurethanes / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry; D012117:Resins, Synthetic / Q000737:chemistry*; D013997:Time Factors; D015034:Zinc Oxide / Q000737:chemistry*; D015035:Zinc Oxide-Eugenol Cement / Q000737:chemistry; D015040:Zirconium / Q000737:chemistry*
chemical_list: D000180:Acrylic Resins; D001672:Biocompatible Materials; D003188:Composite Resins; D003738:Dental Cements; D015921:Dental Implants; D005899:Glass Ionomer Cements; D011076:Polycarboxylate Cement; D011140:Polyurethanes; D019279:Resin Cements; D012117:Resins, Synthetic; C513703:Vivadent; D015035:Zinc Oxide-Eugenol Cement; C103502:Variolink; D008277:Magnesium Oxide; C040235:Ketac-cem; C010102:delrin; D015040:Zirconium; C028541:zirconium oxide; D015034:Zinc Oxide
keywords: Cement; Chipping; Fracture resistance; Implant; Marginal adaptation; Stiffness; Zirconia; e-modulus