ISSN:
0021-9304
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Medicine
,
Technology
Notes:
The glass transition temperature (Tg) of a dental porcelain is a factor in determining the magnitude of residual stresses introduced in a dental porcelain during cooling of a porcelain-fused-to-metal prosthesis. Tg is known to vary with changes in heating or cooling rate. However, available commercial instrumentation does not permit Tg to be obtained at the very high cooling rates commensurate with actual dental laboratory practice. Tg values are reported here for a number of commercial dental porcelains and other materials. These data were obtained by the bending beam technique, employing a special low thermal-mass furnace to permit rapid heating and cooling rates. Measurements were made at rates as high as 600°C/min. Coefficients of determination (r2) for 1/Tg vs. In (heating rate) were excellent. This relation is consistent with previously reported low rate Tg data obtained by a different technique.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jbm.820200303
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