Original scientific paper
Investigation of the Linear Thermal Expansion Coefficient of Four Different Types of Phosphat Investment Materials
Dragutin Komar
; Department of Fixed Prosthodontics, School of Dentistry, University of Zagreb, Croatia
Biserka Lazić
; Department of Fixed Prosthodontics, School of Dentistry, University of Zagreb, Croatia
Adnan Ćatović
; Department of Fixed Prosthodontics, School of Dentistry, University of Zagreb, Croatia
Tomislav Ivaniš
; Department of Fixed Prosthodontics, School of Dentistry, University of Zagreb, Croatia
Ivo Baučić
; Department of Fixed Prosthodontics, School of Dentistry, University of Zagreb, Croatia
Abstract
The fit alloy castings used in fixed prosthodontics is dependent on the physico-chemical features of the investment. The aim of this study was to investigate the polymorphic transformation phases constituting the investment materials by X-ray diffraction analysis on a Philips diffractometer. The coefficient of linear heat expansion for the investment materials studied was obtained using a Chevenard dilatometer. The study was performed on tour types o f investment
materials: Univest 1 P, Begoral, Politerm C and Zeusvest. The highest coefficient of heat expansion was recorder for the specimen o f Begoral (1.13 %), and the lowest for Politerm C (0.99 %). The Politerm C and Zeusvest materials were found to have almost dentical dilatometric characteristics. A large proportion o f low temperature portion o f quartz and crystobalit in the specimens o f Zeusvest and Politerm C investments was demonstrated by the analysis o f dijfractograms.
Keywords
investment materials; dilatometric analysis; X-ray diffraction analysis
Hrčak ID:
98634
URI
Publication date:
15.9.1996.
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