Journal of Dental Research, Vol 68, 1316-1318, Copyright © 1989 by International & American Associations for Dental Research Online Journals
A rapid heating and cooling rate dilatometer for measuring thermal expansion in dental porcelain
S. W. Twiggs, J. R. Searle, R. D. Ringle and C. W. Fairhurst
Department of Restorative Dentistry, School of Dentistry, Augusta, Georgia.
Herein we describe a dilatometer that consists of a low-mass infrared
furnace for rapid heating or cooling, an optical pyrometer, and a laser
interferometer. The dilatometer facilitates observations of thermal
expansion at rates comparable with those in dental laboratory practice over
the temperature range necessary for comparison of thermal expansion of
dental porcelain and alloy. Examples of thermal expansion data obtained at
a 600 degrees C/min heating rate on NIST SRM 710 glass and dental porcelain
are reported. To a limited extent, thermal expansion data above the
glass-transition temperature range of dental porcelain were obtained. A
shift of the glass-transition temperature range to higher temperatures was
observed for both materials, compared with data obtained at 20 degrees
C/min.
