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Soldering and remelting influence on fatigue strength of cobalt-chromium alloys.
Henriques, G E; Consani, S; Rollo, J M; Andrade e Silva, F.
Afiliação
  • Henriques GE; Department of Prosthodontics, Campinas State University, Piracicaba Dentistry School, Sao Paulo, Brazil.
J Prosthet Dent ; 78(2): 146-52, 1997 Aug.
Article em En | MEDLINE | ID: mdl-9260131
STATEMENT OF PROBLEM: For laboratory production, it would be economically advisable to reuse excess cobalt-chromium alloys in manufacturing partial denture frameworks. Furthermore, discrepancies in fit, modifications, repairs, and also economic factors could lead to soldering procedure on the metal framework. PURPOSE: This study evaluated the influence of soldering and remelting procedures on the fatigue strength of Steldent, Dentorium, and Biosil cobalt-chromium alloys, as new alloys and in a mixture of new and previously casted alloy and when submitted or not submitted to conventional soldering procedure. MATERIAL AND METHODS: The soldering procedure was conducted in rod specimens 1.7 mm in diameter made with new, or with a mixture of new and reused alloy (n = 10 per group). The results were compared with those of intact rods. The fatigue strength was carried out with a cyclic testing machine simulating the insertion and the removal of partial dentures. After failure, the fracture surface was examined with a scanning electron microscope. RESULTS: The soldered specimens revealed 1119 loading cycles before fracture. These means differed statistically from those of intact alloys, which disclosed 2733 cycles before failure (p < 0.05). Statistical analysis indicated that the soldering procedure reduced fatigue strength of all new alloys or those in a mixture of new and previously casted alloys. It was also found that the soldering procedure may cause premature failure of a removable partial denture. Photomicrographs from fracture surfaces revealed the presence of inclusions and voids. Conversely, there were no significant differences between new and reused specimens, soldered or not (p > 0.05), which suggested that it may be possible to reuse excess cobalt-chromium alloys without compromising the fatigue strength of the framework.
Assuntos
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Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Soldagem em Odontologia / Ligas de Cromo Tipo de estudo: Diagnostic_studies / Evaluation_studies Limite: Humans Idioma: En Revista: J Prosthet Dent Ano de publicação: 1997 Tipo de documento: Article País de afiliação: Brasil País de publicação: Estados Unidos
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Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Soldagem em Odontologia / Ligas de Cromo Tipo de estudo: Diagnostic_studies / Evaluation_studies Limite: Humans Idioma: En Revista: J Prosthet Dent Ano de publicação: 1997 Tipo de documento: Article País de afiliação: Brasil País de publicação: Estados Unidos