Measurement of the setting expansion of phosphate-bonded investment materials: Part 1 - development of the casting ring test

C. H. Lloyd, J. A. Yearn, G. A. Cowper, J. Blavier, M. Vanderdonckt

    Research output: Contribution to journalArticle

    5 Citations (Scopus)

    Abstract

    The setting expansion is an important property for a phosphate-bonded investment material. This research was undertaken to investigate a test that might be suitable for its measurement when used in a Standard. In the ‘Casting-Ring Test’, the investment sample is contained in a steel ring and expands to displace a precisely positioned pin. Variables with the potential to alter routine reproduction of the value were investigated. The vacuum-mixer model is a production laboratory variable that must not be ignored and for this reason, experiments were repeated using a different vacuum-mixer located at a second test site. Restraint by the rigid ring material increased expansion, while force on the pin reduced it. Expansion was specific to the lining selected. Increased environmental temperature decreased the final value. Expansion was still taking place at a time at which its value might be measured. However, when these factors are set, the reproducibility of values for setting expansion was good at both test sites (coefficient of variation 14%, at most). The results revealed that with the control that is available reliable routine measurement is possible in a Standard test. The inter-laboratory variable, vacuum-mixer model, produced significant differences and it should be the subject of further investigation.
    Original languageEnglish
    Pages (from-to)695-702
    Number of pages8
    JournalJournal of Oral Rehabilitation
    Volume31
    Issue number7
    DOIs
    Publication statusPublished - 2004

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    Vacuum
    Phosphates
    Steel
    Reproduction
    Temperature
    Research

    Keywords

    • Dental materials
    • Investment
    • Casting
    • Setting expansion
    • Phosphate-bonded investment

    Cite this

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    title = "Measurement of the setting expansion of phosphate-bonded investment materials: Part 1 - development of the casting ring test",
    abstract = "The setting expansion is an important property for a phosphate-bonded investment material. This research was undertaken to investigate a test that might be suitable for its measurement when used in a Standard. In the ‘Casting-Ring Test’, the investment sample is contained in a steel ring and expands to displace a precisely positioned pin. Variables with the potential to alter routine reproduction of the value were investigated. The vacuum-mixer model is a production laboratory variable that must not be ignored and for this reason, experiments were repeated using a different vacuum-mixer located at a second test site. Restraint by the rigid ring material increased expansion, while force on the pin reduced it. Expansion was specific to the lining selected. Increased environmental temperature decreased the final value. Expansion was still taking place at a time at which its value might be measured. However, when these factors are set, the reproducibility of values for setting expansion was good at both test sites (coefficient of variation 14{\%}, at most). The results revealed that with the control that is available reliable routine measurement is possible in a Standard test. The inter-laboratory variable, vacuum-mixer model, produced significant differences and it should be the subject of further investigation.",
    keywords = "Dental materials, Investment, Casting, Setting expansion, Phosphate-bonded investment",
    author = "Lloyd, {C. H.} and Yearn, {J. A.} and Cowper, {G. A.} and J. Blavier and M. Vanderdonckt",
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    Measurement of the setting expansion of phosphate-bonded investment materials: Part 1 - development of the casting ring test. / Lloyd, C. H.; Yearn, J. A.; Cowper, G. A.; Blavier, J.; Vanderdonckt, M.

    In: Journal of Oral Rehabilitation, Vol. 31, No. 7, 2004, p. 695-702.

    Research output: Contribution to journalArticle

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    AU - Lloyd, C. H.

    AU - Yearn, J. A.

    AU - Cowper, G. A.

    AU - Blavier, J.

    AU - Vanderdonckt, M.

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