Theoretical consideration and evaluation of thermal diffusivity characteristic coefficients of resin/ionomer restorative biomaterials
AbstractThe aim of this study was to theoretically consider and evaluate the transient temperature-time response of resin/ionomer materials between ~2EC (melting ice temperature) and ~50EC, and indicate their suitability as lining materials. Specimens of materials, cylindrical in geometry, (6 mm diameter and 10 mm in length), were fabricated with teflon moulds. These were subjected to successive temperature-time transients, after allowing them to equilibrate for 2 hours. A centrally embedded thermocouple, in the cylindrical specimens, was then outputted to the data acquisition system. The data capture per specimen of a material was repeated 10 times. The appropriate theory related to the solid of cylindrical geometry was developed and applied in evaluating thermal diffusivity coefficients, A, of materials from the heating and cooling thermal phases during the experiment. Statistical analysis of the data obtained using two-way ANOVA test, showed no marked differences (p < 1.00) between the two thermal diffusivity data sets. Diffusivity magnitudes of the resin/ionomer materials ranged between 0.14 and 0.30 mm2s-1 ,with Charisma, a conventional composite, showing maximum thermal diffusivity of ~0.30 mm2/s, and the least value of 0.15 mm2/s obtained by Compomer F2000. The theory of thermal diffusivity as applied to cylindrical-shaped materials has indicated the transient temperature-time response to heat stimuli of dental restorative biomaterials. Thermals diffusivities of the resin/ionomer materials have also indicated their suitability as liners, as such, the parameter remains a significant factor in the choice of a lining material for restoration.
(Journal of the Ghana Science Association: 2001 3(3): 6-13)