title: Evaluation of bond strength of various margin ceramics to a zirconia ceramic.
abstract: OBJECTIVE
  This study evaluated the bond strengths of four different margin ceramics based on fluoroapatite and feldspath to a zirconia ceramic.
  
  
  METHODS
  Zirconia cores (Zirconzahn) (N=28, n=7/margin ceramic group) were fabricated according to the manufacturers' instructions (diameter: 4mm; thickness: 2mm) and ultrasonically cleaned. Four different margin ceramics (thickness: 5mm) (Cerabien Zr, Noritake; Ceramco PFZ, Ceramco; e.max, Ivoclar Vivadent and Triceram, Dentaurum) were vibrated and condensed in a stainless steel mould and fired onto their zirconia cores. After trying the specimens in the mould for minor adjustments, they were again ultrasonically cleaned and embedded in PMMA. The specimens were stored in distilled water at 37 degrees C for 1 week and shear bond strength (MPa+/-S.D.) tests were performed in a universal testing machine (crosshead speed: 0.5mm/min). Failure modes were recorded under SEM.
  
  
  RESULTS
  Significant effect of margin ceramic types were found on the bond strength values (P<0.05). The mean bond strength values of Ceramco margin ceramic to zirconia was significantly lower (25.4+/-4.5 MPa) (P<0.05) than those of Cerabien (31.6+/-6.4 MPa), e.max (35.9+/-8.4 MPa), and Triceram margin ceramic (38.8+/-7.1 MPa) systems.
  
  
  CONCLUSIONS
  Margin ceramics, compatible with zirconia framework material tested in the present study, exhibited high bond strength values. Variations in thermal expansion coefficients might influence their bond strength values.
authors.affiliation: Ege University, School of Dentistry, Department of Prosthodontics, Izmir, Turkey. erhancomlek@yahoo.com
authors.forename: M Erhan
authors.initials: ME
authors.lastname: Cömlekoğlu
authors.forename: Mine
authors.initials: M
authors.lastname: Dündar
authors.forename: Mutlu
authors.initials: M
authors.lastname: Ozcan
authors.forename: M Ali
authors.initials: MA
authors.lastname: Güngör
authors.forename: Bülent
authors.initials: B
authors.lastname: Gökçe
authors.forename: Celal
authors.initials: C
authors.lastname: Artunç
mesh_terms: D002518:Ceramides / Q000737:chemistry; D001840:Dental Bonding; D018772:Dental Marginal Adaptation; D003776:Dental Porcelain / Q000737:chemistry*; D003799:Dental Stress Analysis; D003801:Dental Veneers; D008422:Materials Testing; D016876:Metal Ceramic Alloys / Q000737:chemistry*; D011176:Post and Core Technique / Q000295:instrumentation; D011474:Prosthesis Design; D033081:Shear Strength; D015040:Zirconium / Q000737:chemistry*
chemical_list: D002518:Ceramides; D016876:Metal Ceramic Alloys; C436063:TriCeram; D003776:Dental Porcelain; C058233:Ceramco; D015040:Zirconium; C028541:zirconium oxide