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Article: Effect of burnout temperatures on strength of phosphate-bonded investments - Part II: Effect of metal temperature

TitleEffect of burnout temperatures on strength of phosphate-bonded investments - Part II: Effect of metal temperature
Authors
KeywordsCasting
Phosphate-bonded investments
Strength
Issue Date1997
PublisherElsevier Ltd. The Journal's web site is located at http://www.elsevier.com/locate/jdent
Citation
Journal Of Dentistry, 1997, v. 25 n. 5, p. 423-430 How to Cite?
AbstractObjectives: It had previously been found that the strength of phosphate-bonded investments is temperature sensitive. However, while the effect of heat from the cast metal is expected to have some effect on continued reactions and melting, there is no published report dealing with this. It was the purpose of this study to consider further the effects of burnout temperature on strength and the contribution of metal casting temperature and investment composition. Methods: The disc-rupture test (Luk, H. W.-K. and Darvell, B. W., Strength of phosphate-bonded investments at high temperature. Dental Materials 1991, 7, 99-102) was employed to determine the effect of burnout temperature (ranging from 400 to 1000°C) on the 'actual' strength of six phosphate-bonded investments; the cast metal temperature was controlled to be the same as that of the mould. Atomic absorption was employed to investigate aspects of the composition of the investments. Results: The 'actual' strength obtained in this test was always higher than the 'service' strength observed in similar testing with the metal at a fixed temperature (1460°C). The 'actual' strength was also temperature sensitive, but with a different pattern of variation compared with the 'service' values. All investments tested were found to behave plastically at high temperatures. Calcium, sodium, zinc and iron were found in appreciable quantities in the investments. Conclusion: Heat from the high-temperature casting metal has a material effect in decreasing the strength of phosphate-bonded investments. Such heating increases the plastic behaviour of the investment and this, together with the casting pressure, may result in a distorted mould and thus inaccurate castings, a hitherto unrecognized source of error. 'Actual' strength gives no guide to the 'service' strength, emphasizing the need for tests under service conditions. Composition affects investment high-temperature strength substantially. © 1997 Elsevier Science Ltd.
Persistent Identifierhttp://hdl.handle.net/10722/154002
ISSN
2015 Impact Factor: 3.109
2015 SCImago Journal Rankings: 1.029
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorLuk, HWKen_US
dc.contributor.authorDarvell, BWen_US
dc.date.accessioned2012-08-08T08:22:45Z-
dc.date.available2012-08-08T08:22:45Z-
dc.date.issued1997en_US
dc.identifier.citationJournal Of Dentistry, 1997, v. 25 n. 5, p. 423-430en_US
dc.identifier.issn0300-5712en_US
dc.identifier.urihttp://hdl.handle.net/10722/154002-
dc.description.abstractObjectives: It had previously been found that the strength of phosphate-bonded investments is temperature sensitive. However, while the effect of heat from the cast metal is expected to have some effect on continued reactions and melting, there is no published report dealing with this. It was the purpose of this study to consider further the effects of burnout temperature on strength and the contribution of metal casting temperature and investment composition. Methods: The disc-rupture test (Luk, H. W.-K. and Darvell, B. W., Strength of phosphate-bonded investments at high temperature. Dental Materials 1991, 7, 99-102) was employed to determine the effect of burnout temperature (ranging from 400 to 1000°C) on the 'actual' strength of six phosphate-bonded investments; the cast metal temperature was controlled to be the same as that of the mould. Atomic absorption was employed to investigate aspects of the composition of the investments. Results: The 'actual' strength obtained in this test was always higher than the 'service' strength observed in similar testing with the metal at a fixed temperature (1460°C). The 'actual' strength was also temperature sensitive, but with a different pattern of variation compared with the 'service' values. All investments tested were found to behave plastically at high temperatures. Calcium, sodium, zinc and iron were found in appreciable quantities in the investments. Conclusion: Heat from the high-temperature casting metal has a material effect in decreasing the strength of phosphate-bonded investments. Such heating increases the plastic behaviour of the investment and this, together with the casting pressure, may result in a distorted mould and thus inaccurate castings, a hitherto unrecognized source of error. 'Actual' strength gives no guide to the 'service' strength, emphasizing the need for tests under service conditions. Composition affects investment high-temperature strength substantially. © 1997 Elsevier Science Ltd.en_US
dc.languageengen_US
dc.publisherElsevier Ltd. The Journal's web site is located at http://www.elsevier.com/locate/jdenten_US
dc.relation.ispartofJournal of Dentistryen_US
dc.rightsJournal of Dentistry. Copyright © Elsevier Ltd.-
dc.subjectCasting-
dc.subjectPhosphate-bonded investments-
dc.subjectStrength-
dc.subject.meshCalcium - Analysisen_US
dc.subject.meshChemistry, Physicalen_US
dc.subject.meshDental Alloys - Analysis - Chemistryen_US
dc.subject.meshDental Casting Investment - Analysis - Chemistryen_US
dc.subject.meshDental Casting Technique - Instrumentationen_US
dc.subject.meshHot Temperatureen_US
dc.subject.meshIron - Analysisen_US
dc.subject.meshMaterials Testingen_US
dc.subject.meshPhosphates - Chemistryen_US
dc.subject.meshPhysicochemical Phenomenaen_US
dc.subject.meshPressureen_US
dc.subject.meshSodium - Analysisen_US
dc.subject.meshSpectrophotometry, Atomicen_US
dc.subject.meshStress, Mechanicalen_US
dc.subject.meshSurface Propertiesen_US
dc.subject.meshZinc - Analysisen_US
dc.titleEffect of burnout temperatures on strength of phosphate-bonded investments - Part II: Effect of metal temperatureen_US
dc.typeArticleen_US
dc.identifier.emailLuk, HWK:wkluka@hkucc.hku.hken_US
dc.identifier.emailDarvell, BW:b.w.darvell@hku.hken_US
dc.identifier.authorityLuk, HWK=rp00008en_US
dc.identifier.authorityDarvell, BW=rp00007en_US
dc.description.naturelink_to_subscribed_fulltexten_US
dc.identifier.pmid9241961-
dc.identifier.scopuseid_2-s2.0-0031230088en_US
dc.identifier.hkuros31473-
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-0031230088&selection=ref&src=s&origin=recordpageen_US
dc.identifier.volume25en_US
dc.identifier.issue5en_US
dc.identifier.spage423en_US
dc.identifier.epage430en_US
dc.identifier.isiWOS:A1997XK59500008-
dc.publisher.placeUnited Kingdomen_US
dc.identifier.scopusauthoridLuk, HWK=7006636056en_US
dc.identifier.scopusauthoridDarvell, BW=7005953926en_US

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