Abstract

PREPARATION OF DENTAL PHOSPHATE-BONDED INVESTMENT TO CAST NICKEL: CHROMIUM ALLOYS AND THE EVALUATION OF ITS MECHANICAL AND PHYSICAL PROPERTIES

Najdat H. Abdul-Razzak, Saadi M. D. Al-Nuzal *, Mohammed A. Mustafa,Flaih H. Ali, and Bushra A. Lafta

Abstract

An investment composition is described for use in dental investment casting (also called lost wax casting), from Iraqi locally available raw materials. The major composition is a phosphate bonded material that contains synthesized mono-ammonium phosphate (MAP) as binder, and silica filler (quartz, cristobalite, or a mixture thereof) as refractory materials. The procedure included many steps among them chemical syntheses, and thermal treatments at high temperature (~1100ºC), followed by chemical analysis for quality control. The high purity investment was successfully, used to cast Nickel: Chromium alloys for dental use. The evaluation of the mechanical and physical properties of the prepared investment were carefully checked according to the required specification of the ISO No. 9694/1996, which was adapted for preparing chemical, physical, and mechanical properties of the prepared dental materials. The chemical analysis of this formulation showed to be in good agreement with many imported investments.

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