Veneering composites - a thermoanalytical examination

Differential thermal analysis and thermal gravimetric analysis were used to characterize veneering composites. Samples weighing 4-20 mg, made from the composite materials Visio-Gem (Espe, Germany), Sinfony (Espe, Germany), Ar tglass (Kulzer, Germany), Dentacolor (Kulzer, Germany) and Targis (Ivoclar, Liechtenstein), were examined. The samples were subjected to various therm al curing times of between 4 s and 25 min, using the relevant devices of th e manufacturers. As a control group, samples of all materials were examined unreacted. In order to avoid post-curing during storage, all samples were subjected, immediately after manufacture, to the appropriate dynamic temper ature programme of the thermoanalytical unit at a heating rate of 10 degree s C min(-1). The materials showed specific material characteristics which c an, for instance, be used to analyse the curing behaviour of the materials. The position of the glass transition, polymerization and post-polymerizati on peaks at temperatures between 30 and 100 degrees C, as well as 150 and 3 00 degrees C, and the filler and matrix content, allow the classification o f the veneering composites. (C) 1999 Kluwer Academic Publishers.