DYNAMIC-MECHANICAL THERMAL-ANALYSIS OF DENTURE SOFT LINING MATERIALS

The purpose of this study was to characterize the deformation properti es of a range of long-term denture soft lining materials using dynamic mechanical thermal analysis. Specimens were subjected to sinusoidal s hear deformation at a frequency of 1 Hz and a strain of 64 microns pea k to peak over a temperature range of 30-70 degrees C. The technique s imulated the type and rate of deformation soft lining materials would experience clinically, thus producing more relevant results than previ ously used methods. Shear modulus G', dissipative modulus G '' and mec hanical loss tangent G ''/G' were obtained for each material. With inc reasing temperature the moduli of the acrylic materials decreased, ind icating an increased compliance and greater deformation. The silicone (Molloplast B) and alternative formulation (Novus) properties were gen erally insensitive to temperature over the range chosen. The mechanica l loss tangent values of the acrylics fell continuously with temperatu re, suggesting that the plasticization process lowered the T-g values below 30 degrees C, the lowest temperature of testing. (C) 1996 Elsevi er Science Limited