J Adv Prosthodont.  2015 Feb;7(1):56-61. 10.4047/jap.2015.7.1.56.

Influence of shape and finishing on the corrosion of palladium-based dental alloys

• Milheiro A
• Muris J
• Kleverlaan CJ
• Feilzer AJ

• KMID: 1974892
• DOI: http://doi.org/10.4047/jap.2015.7.1.56

Abstract

PURPOSE
The purpose of this study was to evaluate the effects of the surface treatment and shape of the dental alloy on the composition of the prosthetic work and its metallic ion release in a corrosive medium after casting.
MATERIALS AND METHODS
Orion Argos (Pd-Ag) and Orion Vesta (Pd-Cu) were used to cast two crowns and two disks. One of each was polished while the other was not. Two as-received alloys were also studied making a total of 5 specimens per alloy type. The specimens were submersed for 7 days in a lactic acid/sodium chloride solution (ISO standard 10271) and evaluated for surface structure characterization using SEM/EDAX. The solutions were quantitatively analysed for the presence of metal ions using ICP-MS and the results were statistically analysed with one-way ANOVA and a Tukey post-hoc test.
RESULTS
Palladium is released from all specimens studied (range 0.06-7.08 microg.cm(-2).week(-1)), with the Pd-Cu alloy releasing the highest amounts. For both types of alloys, ion release of both disk and crown pairs were statistically different from the as-received alloy except for the Pd-Ag polished crown (P>.05). For both alloy type, disk-shaped pairs and unpolished specimens released the highest amounts of Pd ions (range 0.34-7.08 microg.cm(-2).week(-1)). Interestingly, in solutions submerged with cast alloys trace amounts of unexpected elements were measured.
CONCLUSION
Shape and surface treatment influence ion release from dental alloys; polishing is a determinant factor. The release rate of cast and polished Pd alloys is between 0.06-0.69 microg.cm(-2).week(-1), which is close to or exceeding the EU Nickel Directive 94/27/EC compensated for the molecular mass of Pd (0.4 microg.cm(-2).week(-1)). The composition of the alloy does not represent the element release, therefore we recommend manufacturers to report element release after ISO standard corrosion tests beside the original composition.

Keyword

Corrosion; Dental alloys; Palladium

MeSH Terms

Alloys
Corrosion*
Crowns
Dental Alloys*
Ions
Nickel
Palladium
Alloys
Dental Alloys
Ions
Nickel
Palladium

Figure

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  Fig. 1 Photographic representation of the different test specimens with the suspension point.

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  Fig. 2 SEM (SE) and EDAX mapping images (Pd and Ag) of the polished Pd-Ag alloy (Orion Argos) disk before (A) and after immersion for 7 days in 5 mL at 37℃ in a lactic acid solution specified by the ISO 10271 standard (B).

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  Fig. 3 SEM (SE) and EDAX mapping images (Pd and Ag) of the unpolished Pd-Ag alloy (Orion Argos) disk before (A) and after immersion for 7 days in 5 mL at 37℃ in a lactic acid solution specified by the ISO 10271 standard (B).

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