title: Effect of heating palladium-silver alloys on ceramic bond strength.
abstract: BACKGROUND
  The effects of different heat treatments on the internal oxidation and metal-ceramic bond in Pd-Ag alloys with different trace elements require further documentation.
  
  
  OBJECTIVE
  The purpose of this in vitro study was to determine whether heat treatment affects the metal-ceramic bond strength of 2 Pd-Ag alloys containing different trace elements.
  
  
  METHODS
  Thirteen cast specimens (25×3×0.5 mm) from each of 2 Pd-Ag alloy groups (W-1 and Argelite 61+3) were allocated to heat treatments before porcelain application: heating under reduced atmospheric pressure of 0.0014 MPa and 0.0026 MPa and heating under normal atmospheric pressure. Bond strengths were evaluated using a 3-point bending test according to ISO9693. Results were analyzed using 2-way ANOVA and Tukey HSD test (α=.05). Visual observation was used to determine the failure types of the fractured specimens. Scanning electron microscopy and energy dispersive spectroscopy were used to study morphologies, elemental compositions, and distributions in the specimens.
  
  
  RESULTS
  The W-1 group had a mean bond strength significantly higher than that of Argelite 61+3 (P<.001). Heating under reduced atmospheric pressures of 0.0014 MPa and 0.0026 MPa resulted in similar bond strengths (P=.331), and both pressures had significantly higher bond strengths than that of heating under normal atmospheric pressure (P=.002, P<.001). Heating under different air pressures resulted in Pd-Ag alloys that contained either Sn or In and Ga, with various degrees of internal oxidation and different quantities of metallic nodules.
  
  
  CONCLUSIONS
  Heating under reduced atmospheric pressure effectively improved the bond strength of the ceramic-to-Pd-Ag alloys.
authors.affiliation: Resident, Department of Prosthodontics, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China; and Resident, Department of Stomatology, Jieyang People's Hospital, Jieyang, China.
authors.forename: Jie-yin
authors.initials: JY
authors.lastname: Li
authors.affiliation: Technical Director, Dingyuan Dental Lab Ltd, Dongguan, China.
authors.forename: Rui-nan
authors.initials: RN
authors.lastname: Li
authors.affiliation: Assistant Professor, Department of Prosthodontics, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China.
authors.forename: Shao-hai
authors.initials: SH
authors.lastname: Chang
authors.affiliation: Resident, Department of Prosthodontics, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China.
authors.forename: Pei-lin
authors.initials: PL
authors.lastname: Zhuang
authors.affiliation: Resident, Department of Prosthodontics, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China.
authors.forename: Juan-kun
authors.initials: JK
authors.lastname: Liao
authors.affiliation: Resident, Department of Prosthodontics, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China.
authors.forename: Xiu-hua
authors.initials: XH
authors.lastname: Ye
authors.affiliation: Assistant Professor, Department of Prosthodontics, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China. Electronic address: dutaoye@163.com.
authors.forename: Jian-tao
authors.initials: JT
authors.lastname: Ye
mesh_terms: D003764:Dental Materials / Q000737:chemistry / Q000528:radiation effects*; D006361:Heating; D006358:Hot Temperature; D008422:Materials Testing; D016876:Metal Ceramic Alloys / Q000737:chemistry / Q000528:radiation effects*; D064347:Microscopy, Electrochemical, Scanning; D010165:Palladium / Q000528:radiation effects*; D033081:Shear Strength / Q000528:radiation effects*; D012834:Silver / Q000528:radiation effects*; D013052:Spectrometry, X-Ray Emission; D013314:Stress, Mechanical
chemical_list: D003764:Dental Materials; D016876:Metal Ceramic Alloys; D012834:Silver; D010165:Palladium