Microscopy analysis of dental titanium casting investment materials

Journal Article · Fri Sep 01 00:00:00 EDT 1989 · Scanning Microscopy; (USA)

OSTI ID:7031619

Mueller, H J ^[1]

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1. Council on Dental Materials, Instruments, and Equipment, American Dental Association, Chicago, IL (USA)

Scanning electron microscopy (SEM) analysis and qualitative energy dispersive x-ray microanalysis (EDS) of investment materials for dental titanium casting were performed. Two commercial investment materials, Ohara and Castmatic, and an experimental zirconia material were analyzed. The microstructural constituents and the unfired and fired structures were included. Larger refractory particles and matrix embedding smaller particles were observed with each material. Detection of aluminum, silicon, magnesium, zirconium and oxygen provided a basis to reason the presence of alumina (Al2O3), silica (SiO2), magnesia (MgO), and zirconia (ZrO2). Hence, Ohara contained quartz and an alumino-silicate, Castmatic contained magnesia and quartz and experimental zirconia contained zirconia and an alumino-silicate, taken to be kyanite, as components providing refractoriness and expansion. Even though unequivocal detection of phosphorous in the spectra for Ohara was not obtained (P K alpha = 2.013 keV; Zr L alpha = 2.042 keV), an emission peak at 2.0 keV was taken to be due to P and related, along with MgO, to bonding by magnesium phosphate. For Castmatic, unfired strength was thought to be due to calcium chloride and calcium silicate and fired strength to forsterite, (2MgO.SiO2). Detection of calcium and chlorine also suggested bonding of experimental zirconia via calcium chloride. Extensive microcracking occurred around refractory particles and through matrix in experimental zirconia which is likely to have resulted from the firing of kyanite to 1400 degrees C, to the monoclinic to tetragonal transformation of any unstabilized ZrO2, or to the thermal expansion mismatch between kyanite and matrix.

• OSTI ID: 7031619
• Journal Information: Scanning Microscopy; (USA), Vol. 3:3; ISSN 0891-7035
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
TEETH
IMPLANTS
ZIRCONIUM
CHEMICAL ANALYSIS
DENTISTRY
ELECTRON MICROPROBE ANALYSIS
MOLECULAR STRUCTURE
SCANNING ELECTRON MICROSCOPY
TITANIUM
DIGESTIVE SYSTEM
ELECTRON MICROSCOPY
ELEMENTS
MEDICINE
METALS
MICROANALYSIS
MICROSCOPY
ORAL CAVITY
TRANSITION ELEMENTS
400101* - Activation
Nuclear Reaction
Radiometric & Radiochemical Procedures