A comprehensive three-year research project is proposed to investigate the metallurgical structures of eight representative high-Pd alloys and establish a scientific basis for their creep behavior and conventional mechanical properties.The first area of research will employ transmission electron microscopy (TEM) to determine the structures of metallurgical phases in these alloys for the as-cast condition and after the porcelain firing cycle heat treatment. The TEM experiments will be complemented by scanning electron microscopy (SEM) and x-ray energy- dispersive spectroscopy to obtain the elemental compositions of the alloy phases. Special model high-Pd alloys will also be studied. The second area of research will focus on the high-temperature creep and room temperature mechanical properties of the commercial high-Pd alloys.Creep of these alloys during the porcelain firing cycles can result in an unacceptable clinical fit of the castings, and creep behavior will be determined for flexural and tensile loading, and for temperature and stress ranges appropriate to the fabrication of fixed dental prostheses. Use of tensile loading permits comparison of observed creep rates to predictions from materials science for possible creep mechanisms. TEM studies will establish the relationships between metallurgical structures and creep rates for these alloys. Tensile test specimens which meet the ANSI/ADA specification no. 5 for dental alloys will be cast, and the elastic modulus, yield strength, tensile strength, percentage elongation, and Vickers hardness will be determined for each alloy in the as-cast and heat-treated conditions. Fracture surfaces of these specimens will be examined by SEM, Auger electron spectroscopy, and x-ray photoelectron spectroscopy to obtain complementary information about the failure processes. TEM will be employed to characterize the dislocation interaction processes which control the strengthening mechanisms for these alloys.
Specific Aim #1 is to determine and characterize the metallurgical phases present in representative commercial high-palladium alloys and model alloy systems.
Specific Aim #2 is to determine the elevated-temperature creep behavior of these high-Pd alloys and the relationships of creep rates and mechanisms to the alloy compositions and metallurgical structures.
Specific Aim #3 is to establish the relationships among compositions, metallurgical phases and microstructures for the conventional mechanical properties of the high-Pd alloys.

Agency
National Institute of Health (NIH)
Institute
National Institute of Dental & Craniofacial Research (NIDCR)
Type
Research Project (R01)
Project #
5R01DE010147-02
Application #
2131098
Study Section
Oral Biology and Medicine Subcommittee 1 (OBM)
Project Start
1994-08-01
Project End
1997-07-31
Budget Start
1995-08-01
Budget End
1996-07-31
Support Year
2
Fiscal Year
1995
Total Cost
Indirect Cost
Name
Ohio State University
Department
Dentistry
Type
Schools of Dentistry
DUNS #
098987217
City
Columbus
State
OH
Country
United States
Zip Code
43210
Liu, Ruohong; Johnston, William M; Holloway, Julie A et al. (2010) The effect of metal recasting on porcelain-metal bonding: a force-to-failure study. J Prosthet Dent 104:165-72
Li, D; Baba, N; Brantley, W A et al. (2010) Study of Pd-Ag dental alloys: examination of effect of casting porosity on fatigue behavior and microstructural analysis. J Mater Sci Mater Med 21:2723-31
Ucar, Yurdanur; Brantley, William A; Bhattiprolu, Sreenivas N et al. (2009) Characterization of cast-to implant components from five manufacturers. J Prosthet Dent 102:216-23
Guo, W H; Brantley, W A; Li, D et al. (2007) Annealing study of palladium-silver dental alloys: Vickers hardness measurements and SEM microstructural observations. J Mater Sci Mater Med 18:111-8
Li, Dongfa; Brantley, William A; Guo, Wenhua et al. (2007) Fatigue limits and SEM/TEM observations of fracture characteristics for three Pd-Ag dental casting alloys. J Mater Sci Mater Med 18:119-25
Stavridakis, Minos M; Papazoglou, Efstratios; Seghi, Robert R et al. (2004) Effect of different high-palladium metal-ceramic alloys on the color of opaque and dentin porcelain. J Prosthet Dent 92:170-8
Guo, W H; Brantley, W A; Clark, W A T et al. (2003) Transmission electron microscopic investigation of a Pd-Ag-In-Sn dental alloy. Biomaterials 24:1705-12
Guo, W H; Brantley, W A; Clark, W A T et al. (2003) Transmission electron microscopic studies of deformed high-palladium dental alloys. Dent Mater 19:334-40
Tufekci, Eser; Mitchell, John C; Olesik, John W et al. (2002) Inductively coupled plasma-mass spectroscopy measurements of elemental release from 2 high-palladium dental casting alloys into a corrosion testing medium. J Prosthet Dent 87:80-5
Sun, Desheng; Monaghan, Peter; Brantley, William A et al. (2002) Potentiodynamic polarization study of the in vitro corrosion behavior of 3 high-palladium alloys and a gold-palladium alloy in 5 media. J Prosthet Dent 87:86-93

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