Penetration of commercial and dental waxes.

Thermomechanical analysis (TMA) measures the mechanical response of a material as it is programmed linearly through a selected temperature range.' The techniques used in TMA include linear expansion, volumetric expansion, tensile elongation, torsional modulus, and penetration. Comparison of TMA penetration curves with curves of transition temperatures obtained from differential thermal analysis (DTA), is a powerful, new technique for studying the effect of thermal transitions of a material on its mechanical properties. DTA of commercial and dental waxes has established the presence of solid-solid transition temperatures as well as melting transitions.2 The phase changes associated with these transition temperatures might be expected to influence the mechanical behavior of wax. In this study we examine the relationship between penetration and transition temperatures for various commercial, dental, and combined waxes and provide fundamental information on the formulation and testing of dental waxes.