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Thermal Diffusivity of Glass-ionomer Cements

Dental School, The London Hospital Medical College, Turner Street, London E1 2AD, England

M. Braden

Dental School, The London Hospital Medical College, Turner Street, London E1 2AD, England

Thermal diffusivity, a property related to the thermal insulative efficiency of a material, was measured in nine glass-ionomer cements and compared with results from a silicate and a polycarboxylate cement. Each cement was mixed at various powder-liquid ratios (P/L) and moulded into a rectangular prism of approximate dimensions 2 cm cube with a thermocouple embedded in it. The prism was immersed in a constant-temperature bath at 1°C, and the fall in temperature was observed over a period of three min. Except for the initial and later stages, the plot of the logarithmic difference between external and internal temperatures of each block of cement against time showed a straight line in accord with theoretical prediction. From the slope, the thermal diffusivity of the material was calculated. The values for the silicate, polycarboxylate, and glass-ionomer-metal (cermet) showed a marked rise with increasing P/L, whereas at higher P/L, glass ionomer cements showed gradual change, with values being only slightly higher than the thermal diffusivity of dentin. Glass-ionomer cements are good thermal insulators over a wide range of PIL, and close agreement between experimental and theoretical data shows that glass-ionomer cements are homogeneous isotropic materials.

REFERENCES

• Bertenshaw, B.W. and Combe, E.C. (1972): Studies on Polycarboxylate and Related Cement. 2. Analysis of Cement Powders, J Dent 1:65-68.[CrossRef][Medline] [Order article via Infotrieve]
• Braden, M. (1964): Heat Conduction in Teeth and the Effect of Lining Materials, J Dent Res 43:315-322.[Free Full Text]
• Braden, M. (1976): Biophysics of the Tooth, Oral Physiol 2:1-37.
• Carslaw, H.S. and Jaeger, J.C. (1959): Conduction of Heat in Solids, 2nd ed., Oxford: Oxford University Press.
• Civjan, S.; Barone, J.J.; Reinke, P.E.; and Selting, W.J. (1972): Thermal Properties of Nonmetallic Restorative Materials, J Dent Res 5:1030-1037.
• Craig, R.G. (1980): Restorative Dental Materials, 6th ed., St. Louis: C.V. Mosby Co., p. 54.
• McLean, J.W. and Gasser, O. (1985): Glass-cermet Cements, Quintessence Int 16:333-343.[Medline] [Order article via Infotrieve]
• Pearson, G.J.; Wills, D.J.; Braden, M.; and McCabe, J.F. (1980): The Relationship Between the Thermal Properties of Composite Filling Materials, J Dent 8:178-181.[CrossRef][Medline] [Order article via Infotrieve]
• Touloukian, Y.S.; Powell, R.W.; Ho, C.Y.; and Nico-Laou, N. (1973): Thermophysical Properties of Matter, Vol. 10: Thermal Diffusivity. New York: IFI/Plenum.
• Watts, D.C. and Smith, R. (1981): Thermal Diffusivity in Finite Cylindrical Specimens of Dental Cements, J Dent Res 60:1972-1976.[Abstract/Free Full Text]
• Watts, D.C. and Smith, R. (1984): Thermal Diffusion in Some Polyelectrolyte Dental Cements: The Effect of Powder/Liquid Ratio, J Oral Rehabil 11:285-288.[Medline] [Order article via Infotrieve]

Journal of Dental Research, Vol. 66, No. 5, 1040-1043 (1987)
DOI: 10.1177/00220345870660051001


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This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Saved Citations Download to citation manager Request Permissions Request Reprints Add to My Marked Citations Citing Articles Citing Articles via Google Scholar Citing Articles via Scopus Google Scholar Articles by Tay, W.M. Articles by Braden, M. Search for Related Content PubMed PubMed Citation Articles by Tay, W.M. Articles by Braden, M. Pubmed/NCBI databases Compound via MeSH Substance via MeSH Social Bookmarking                         What's this?