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Three-Body Wear of a Hand-Consolidated Silver Alternative to Amalgam

Published

Author(s)

Hockin D. Xu, F Eichmiller, Anthony A. Giuseppetti, L K. Ives, Edward E. Parry, Gary E. Schumacher

Abstract

Recent studies have investigated a mercury-free silver alternative to amalgam, but the silver powders required a relatively high compaction pressure to consolidate. The aim of the present study was to consolidate a precipitated silver powder into a cohesive solid using a air-driven pneumatic condenser fitted with an amalgam plugger at a clinically realistic load, and to study the mechanisms and rates of three-body wear of the consolidated silver in comparison with that of an amalgam. The silver powder was annealed, rinsed with a dilute acid, and consolidated either in a prepared tooth cavity or in a specimen mold at a load of 15 N. A four-station wear machine was used where each specimen was immersed in a slurry containing polymethyl methacrylate beads, then a steel pin was loaded and rotated against the specimen at a maximum load of 76 N. The flexural strength in MPa (mean sd; n = 10) was 86 20 for amalgam, 180 45 for silver with a polished surface, and 202 21 for silver with a burnished surface. After 4 x 105 wear cycles, the wear scar depth in m was 134 54 for amalgam, 143 8 for polished silver, and 131 9 for burnished silver, which were not significantly different (Tukey's multiple comparison test; family confidence coefficient = 0.95). SEM examination revealed cracks and fracture pits in the worn surface of amalgam, in contrast to a smooth surface in silver. Wear and material removal in amalgam occurred by microfracture and dislodgement of cracked segments, while wear in the silver occurred by ductile deformation and flow of materials. To conclude, the hand-consolidated silver possesses a three-body wear resistance similar to that of amalgam, and a higher resistance to wear-induced damage and cracking than amalgam. The mechanism of wear in amalgam is microfracture and material dislodgement, while that in silver is ductile deformation and flow of material.
Citation
Journal of Dental Research
Volume
78
Issue
No. 9

Keywords

amalgam alternative, clinical hand consolidation, damage modes, silver, three-body, wear mechanism

Citation

Xu, H. , Eichmiller, F. , Giuseppetti, A. , Ives, L. , Parry, E. and Schumacher, G. (1999), Three-Body Wear of a Hand-Consolidated Silver Alternative to Amalgam, Journal of Dental Research (Accessed April 25, 2024)
Created September 1, 1999, Updated February 17, 2017