Thermophysical properties of dental filling materials. Part II: thermal expansivity
Andrzej J Panas, Janusz Terpiłowski, Jan Trykowski, Paweł Zaborowski, Stanisław Żmuda
The thermal linear expansivity of three light-curable dental filling materials is reported. The materials under test are: the compomer Compoglass® F, and two hybrid composites, Tetric and Valux™ Plus. The measurements were performed with the use of an absolute laser-interferometry dilatometer. With it, high thermal resolution of measurements has been achieved. Experiments have been carried out on heating and on cooling. Both the coefficient of linear thermal expansion (CLTE) and the linear expansion (LE) have been determined. Attention has been paid to the effect of multiple heating – cooling cycles and thermal ageing. The investigation revealed the effect of initial heating on reduction in CLTE. For the purpose of numerical calculations the results have been expressed with the use of approximation functions. The present study complements the investigation of strictly thermal properties of the above-mentioned materials.