title: Structure and effects of non-gamma-2 amalgam.
abstract: The metallurgical structure of a non-gamma-2 amalgam was investigated by using metallurgical microscopy, surface, point, and line analyses by an electron probe microanalyzer, and a microhardness test. Referring to these findings, their effects on clinical results were then discussed. Findings were as follows: The residual dispersant particle was less hard than the gamma 1 matrix, but the ring around it was much harder than the gamma 1 matrix or the residual gamma particle. The improved mechanical properties seem to be the result of the presence of this ring. The gamma 2 phase was absent in this amalgam. The absence of gamma 2 phase seems to improve chemical resistance, to prevent the deformation by mercuroscopic expansion of amalgam margins, and thus to decrease their fracture potential. The minute gamma 1 crystals found adjacent to the ring around the residual dispersant particle seem to indicate that they were late in crystallization, resulting in low early strength.
mesh_terms: D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003300:Copper / Q000032:analysis; D003723:Dental Amalgam / Q000032:analysis; D004577:Electron Probe Microanalysis; D006244:Hardness; D012834:Silver / Q000032:analysis; D013499:Surface Properties; D014001:Tin / Q000032:analysis
chemical_list: D012834:Silver; D014001:Tin; D003300:Copper; D003723:Dental Amalgam