title: Influence of alkali metal ions on the fracture properties of glass polyalkenoate (ionomer) cements.
abstract: The influence of substituting sodium for calcium on the properties of glass polyalkenoate cements was investigated. Two series of glass compositions based on PSiO2 x QAl2O3 x 0.75P2O5 x (1 - Z)CaO x XCaF2ZNa2O were studied. The fluorine content was fixed at X = 0.50 and 0.75 and the sodium content varied by altering Z. The glass polyalkenoate cements formed from these glasses were characterized using a linear elastic fracture mechanics (LEFM) approach. In addition, compressive strengths of the cements were determined. The properties of the cements based on the high fluorine content glasses (X = 0.75) were relatively insensitive to sodium content. The Young's modulus, un-notched fracture strength and fracture toughness of the cements produced with the lower fluorine content glasses (X = 0.5) reduced with sodium content, which was consistent with sodium acting to disrupt ionic cross-linking in the polyacrylate matrix. The compressive strength was not as dependent on sodium content as the LEFM parameters.
authors.affiliation: Phoenix Dental, Shannon Industrial Estate, Ireland.
authors.forename: E
authors.initials: E
authors.lastname: De Barra
authors.forename: R G
authors.initials: RG
authors.lastname: Hill
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D002412:Cations / Q000737:chemistry; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D005461:Fluorine / Q000737:chemistry; D005899:Glass Ionomer Cements / Q000737:chemistry*; D008422:Materials Testing; D019563:Mechanics; D012964:Sodium / Q000737:chemistry*
chemical_list: D001672:Biocompatible Materials; D002412:Cations; D005899:Glass Ionomer Cements; D005461:Fluorine; D012964:Sodium