title: A comparative study on the bond strength of porcelain to the millingable Pd-Ag alloy.
abstract: OBJECTIVE
  The porcelain fused to gold has been widely used as a restoration both with the natural esthetics of the porcelain and durability and marginal fit of metal casting. However, recently, due to the continuous rise in the price of gold, an interest towards materials to replace gold alloy is getting higher. This study compared the bond strength of porcelain to millingable palladium-silver (Pd-Ag) alloy, with that of 3 conventionally used metal-ceramic alloys.
  
  
  METHODS
  Four types of metal-ceramic alloys, castable nonprecious nickel-chrome alloy, castable precious metal alloys containing 83% and 32% of gold, and millingable Pd-Ag alloy were used to make metal specimens (n=40). And porcelain was applied on the center area of metal specimen. Three-point bending test was performed with universal testing machine. The bond strength data were analyzed with a one-way ANOVA and post hoc Scheffe's tests (α=.05).
  
  
  RESULTS
  The 3-point bending test showed the strongest (40.42 ± 5.72 MPa) metal-ceramic bond in the nonprecious Ni-Cr alloy, followed by millingable Pd-Ag alloy (37.71 ± 2.46 MPa), precious metal alloy containing 83% of gold (35.89 ± 1.93 MPa), and precious metal alloy containing 32% of gold (34.59 ± 2.63 MPa). Nonprecious Ni-Cr alloy and precious metal alloy containing 32% of gold showed significant difference (P<.05).
  
  
  CONCLUSIONS
  The type of metal-ceramic alloys affects the bond strength of porcelain. Every metal-ceramic alloy used in this study showed clinically applicable bond strength with porcelain (25 MPa).
authors.affiliation: Department of Prosthodontics, College of Dentistry, Dankook University, Cheonan, Republic of Korea.
authors.forename: Jun-Tae
authors.initials: JT
authors.lastname: Hong
authors.affiliation: Department of Prosthodontics, College of Dentistry, Dankook University, Cheonan, Republic of Korea.
authors.forename: Soo-Yeon
authors.initials: SY
authors.lastname: Shin
keywords: Bending test; Metal ceramic alloys; Palladium-silver alloy; Porcelain bond strength