title: Surface chemistry of a high-copper dental amalgam.
abstract: In amalgam, mercury is intended to take the form of stable intermetallic compounds. Any mercury leakage must therefore come from free mercury not involved in such compounds. Thus, a knowledge of the exact surface chemistry of dental amalgam is necessary if this phenomenon is to be understood. From XPS and EDS analyses, a model of the surface chemistry of amalgam is proposed which fully characterizes all the phases that are present. The data show the surface to have a composition different from that of the bulk, being comprised of a hydrocarbon deposit and adsorbed water covering the intermetallic phase gamma2 (Sn(6-8)Hg), tin (iv) oxide, and mercury in a free state. After amalgamation, the amount of mercury at the surface decreases with time and eventually attains a constant concentration, where it is all involved in the gamma2 phase, leaving no free mercury. A model is proposed for the surface of amalgam and the changes in this model with time.
authors.affiliation: Laboratory for Surface & Interface Analysis, Department of Engineering Materials, Sheffield, United Kingdom.
authors.forename: A J
authors.initials: AJ
authors.lastname: McDermott
authors.forename: S
authors.initials: S
authors.lastname: Kothari
authors.forename: R D
authors.initials: RD
authors.lastname: Short
authors.forename: R
authors.initials: R
authors.lastname: van Noort
authors.forename: M R
authors.initials: MR
authors.lastname: Alexander
mesh_terms: D003300:Copper / Q000032:analysis / Q000737:chemistry*; D003723:Dental Amalgam / Q000032:analysis / Q000737:chemistry*; D003775:Dental Polishing; D004577:Electron Probe Microanalysis; D008855:Microscopy, Electron, Scanning; D008956:Models, Chemical; D008961:Models, Structural; D013499:Surface Properties; D013997:Time Factors
chemical_list: D003300:Copper; D003723:Dental Amalgam