title: [Dimensional changes of silver and gallium-based alloy].
abstract: Gallium-based dental alloys were created with the aim of solving the problem of toxicity of mercury. The material shows mechanical properties similar to those of dental amalgam, but researches point out two unfavorable characteristics: great corrosion and excessive post-setting expansion, and the latter is capable of cracking dental structures. The aim of this study was to evaluate, during 7 days, the in vitro dimensional alteration of a gallium dental alloy (Galloy, SDI, Australia), in comparison with a dental amalgam containing zinc (F400, SDI, Australia), as a function of the contact with saline solution (0.9% NaCl) during the setting period. The storage experimental conditions were: storage in dry environment, immersion in saline solution and contamination during condensation. Additionally, the effects of contamination during the trituration of dental amalgam and the effects of protecting the surface of the gallium alloy with a fluid resin were studied. Specimens were stored at 37 degrees C +/- 1 degree C, and measuring was carried out, sequentially, every 24 h during 7 days. When the gallium alloy was either contaminated or immersed, an expansion significantly greater than that observed in the other experimental conditions was noticed after 7 days. The application of a fluid resin to protect the surface of the cylinders was able to avoid the increase in expansion caused by superficial moisture. The amalgam alloy did not show significant dimensional alterations, except when it was contaminated during trituration.
authors.affiliation: Departamento de Materiais Dentários, Faculdade de Odontologia, USP.
authors.forename: R Y
authors.initials: RY
authors.lastname: Ballester
authors.forename: R A
authors.initials: RA
authors.lastname: Markarian
authors.forename: A D
authors.initials: AD
authors.lastname: Loguercio
mesh_terms: D000497:Alloys / Q000737:chemistry; D003722:Dental Alloys / Q000737:chemistry; D005708:Gallium / Q000737:chemistry; D008422:Materials Testing; D012834:Silver / Q000737:chemistry
chemical_list: D000497:Alloys; D003722:Dental Alloys; C110328:Metallodent-C; D012834:Silver; D005708:Gallium
vernacular_title: Alteração dimensional de amálgama de prata e liga à base de gálio.