title: Two-body sliding wear of a direct-filling silver alternative to amalgam.
abstract: OBJECTIVE
  This study investigated the wear resistance of a mercury-free silver direct-filling material and a dental amalgam.
  
  
  METHODS
  A precipitated silver powder was rinsed with dilute fluoboric acid and consolidated into a cohesive solid. For tooth cavity restoration and flexural testing, the silver was consolidated with a dental amalgam plugger at a load of 15 N. For wear testing, because of the relatively large specimen size, the silver was pressed at a pressure of 150 MPa, yielding a density similar to that obtained by hand consolidation.
  
  
  RESULTS
  The silver had a flexural strength twice that of amalgam. Pin-on-disk wear resulted in a smooth surface and hardening in silver, as measured by indentation inside the wear tracks, in contrast to the damage that was found in amalgam. The wear track cross-sectional area (n = 12) at 10(6) revolutions was not statistically significantly different among amalgam, polished silver, and burnished silver.
  
  
  CONCLUSIONS
  The consolidated silver exhibited work hardening and surface densification during wear and, as a result, was more resistant to wear-induced damage than amalgam.
authors.affiliation: Paffenbarger Research Center, American Dental Association Health Foundation, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA. hockin.xu@nist.gov
authors.forename: H H
authors.initials: HH
authors.lastname: Xu
authors.forename: A A
authors.initials: AA
authors.lastname: Giuseppetti
authors.forename: F C
authors.initials: FC
authors.lastname: Eichmiller
authors.forename: L K
authors.initials: LK
authors.lastname: Ives
mesh_terms: D000704:Analysis of Variance; D003722:Dental Alloys / Q000737:chemistry*; D003723:Dental Amalgam / Q000737:chemistry*; D019554:Dental Restoration Wear; D004548:Elasticity; D006244:Hardness; D016018:Least-Squares Analysis; D008422:Materials Testing; D018583:Pliability; D012834:Silver / Q000737:chemistry*; D018709:Statistics, Nonparametric; D013718:Tensile Strength
chemical_list: D003722:Dental Alloys; C033470:Dispersalloy; D012834:Silver; D003723:Dental Amalgam