title: Comparison of bond strength of a pressed ceramic fused to metal versus feldspathic porcelain fused to metal.
abstract: OBJECTIVE
  To compare the debonding/crack initiation strength (D/CIS) of a low-fusing pressable leucite-based glass ceramic (PC) fused to metal to a feldspathic porcelain (FP) fused to metal.
  
  
  METHODS
  As per ISO 9693:1999, 40 rectangular metal specimens (25.0 mm x 0.5 mm x 3.0 mm) were prepared. Twenty of the specimens were cast in a base metal nickel-chromium alloy (BA), and 20 were cast in a noble metal palladium-silver alloy (NA). Ten randomly selected NA and BA alloy specimens had FP applied. The remaining 10 NA and BA alloy specimens had ash-free wax patterns applied, the metal-wax complexes invested, and were pressed with a PC. The dimensions of the ceramic specimens were 8.0 mm x 1.0 mm x 3.0 mm, creating a combined metal-ceramic complex thickness of 1.5 mm. All specimens were subject to a three-point bending test at a crosshead speed of 1.5 mm/min. Fracture loads were recorded in Newtons and D/CISs calculated by the formula tau(b)=k x F(fail).
  
  
  RESULTS
  Mean D/CISs, measured in MPa (standard deviations): NA-FP 32.56 (4.62), NA-PC 30.23 (5.06), BA-FP 30.98 (4.41), and BA-PC 31.81 (3.48). A two-way ANOVA (p > 0.05) did not demonstrate significant difference between groups.
  
  
  CONCLUSIONS
  The debonding/crack initiation strength of a low-fusing pressable leucite-based glass ceramic fused to metal was equivalent to that of a feldspathic porcelain fused to metal.
authors.affiliation: Advanced Education Program in Prosthodontics, New York University College of Dentistry, New York, NY, USA. danielmschweitzer@yahoo.com
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Schweitzer
authors.forename: Gary R
authors.initials: GR
authors.lastname: Goldstein
authors.forename: John L
authors.initials: JL
authors.lastname: Ricci
authors.forename: N R F A
authors.initials: NR
authors.lastname: Silva
authors.forename: Eugene L
authors.initials: EL
authors.lastname: Hittelman
mesh_terms: D000538:Aluminum Silicates / Q000737:chemistry*; D002516:Ceramics / Q000737:chemistry*; D002858:Chromium Alloys / Q000737:chemistry; D003722:Dental Alloys / Q000737:chemistry; D001840:Dental Bonding; D003734:Dental Casting Investment / Q000737:chemistry; D003776:Dental Porcelain / Q000737:chemistry*; D005898:Glass / Q000737:chemistry; D006801:Humans; D008422:Materials Testing; D016876:Metal Ceramic Alloys / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D010165:Palladium / Q000737:chemistry; D018583:Pliability; D017680:Potassium Compounds / Q000737:chemistry*; D012834:Silver / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D014741:Video Recording
chemical_list: D000538:Aluminum Silicates; D002858:Chromium Alloys; D003722:Dental Alloys; D003734:Dental Casting Investment; D016876:Metal Ceramic Alloys; D017680:Potassium Compounds; D003776:Dental Porcelain; C016447:feldspar; C078519:leucite; D012834:Silver; D010165:Palladium