STABILITY OF DENTAL WAXES FOLLOWING REPEATED HEATINGS

The flow and strength properties of dental waxes were examined followi ng excessive and repeated heatings of the materials. For one product, the flow at 40 +/- 0.5-degrees-C was reduced by 25.3% following heatin g about 200-degrees-C. A decrease of the elastic modulus at 20 +/- 1-d egrees-C by approximately 66% was observed in some cases after the hea ting temperature had been increased to 300-degrees-C. Property variati ons were related to compositional changes, which were investigated by infrared spectroscopy and thermal analysis. Exposure of dental waxes t o temperatures higher than 200-degrees-C, particularly if it is repeat ed, may affect the composition and properties, resulting in inferior m aterials.