Jasenka Živko-Babić

Microstructure of lucite glass-ceramics for dental use

Abstract Microstructure of lucite glass-ceramics for dental use was investigated using X-ray diffraction, FT-IR spectroscopy and laser Raman spectroscopy. Main features of the FT-IR and laser Raman spectra were similar to those of silicate glasses containing Al 3+ , or other M 3+ (M = metal), as network forming ions. Two weak IR bands at 640 and 543 cm −1 were typical of all lucite-type glass-ceramics and these bands disappeared with the conversion of glass-ceramics into the glass state. The laser Raman spectrum of lucite-type glass showed a broad band with center at ≈ 4600 cm −1 due to fluorescence/luminescence spectral feature with two luminescence sharp peaks at 5037 and 5007 cm −1 . The results were compared with those obtained for different silicate glasses.

Quantitative thin-layer chromatographic identification of dental base alloys

In the corrosively aggressive medium of the oral cavity, the use of identical dental alloys requires identification of the existing metal construction. One of the methods allowing this identification is quantitative thin-layer chromatography with anodic sampling. Using a 4.5-V battery and suitable electrolytes, seven dental alloys for fixed and removable dentures based on cobalt were analysed. Chromatograms of alloy samples were developed with a mixture of acetone and 2 M HCl. Scanning of the thin-layer chromatographic spots produced chromatographic curves and the area under the curve was proportional to the content of cobalt in the alloy studied. Regression analysis showed a very high coefficient of correlation (r=0.999) between the area of the spot and the proportion of cobalt.

Anodic sampling of titanium by thin-layer chromatography

Titanium as the pure metal or as commercial titanium alloys has been widely used in dentistry. To determine the composition of incorporated reconstructions there is a need for non-destructive sampling and identification of unknown or suspect elements. This paper reports an analytical procedure for detection of titanium. The method involves anodic sampling, and separation and identification of titanium by thin-layer chromatography (TLC) on precoated cellulose layers. Two thin plates and one cast of elemental titanium and one dental alloy containing titanium were analyzed. Chromatograms of samples were developed with a mixture of iso-amyl alcohol, acetonitrile and hydrochloric acid as mobile phase. Excellent detection and identification of titanium as a pink spot was achieved after spraying with a saturated ethanolic solution of alizarin and exposure to NH3 vapor.