Stability of dental waxes following repeated heatings.

The flow and strength properties of dental waxes were examined following excessive and repeated heatings of the materials. For one product, the flow at 40 +/- 0.5 degrees C was reduced by 25.3% following heating above 200 degrees C. A decrease of the elastic modulus at 20 +/- 1 degree C by approximately 66% was observed in some cases after the heating temperature had been increased to 300 degrees C. Property variations were related to compositional changes, which were investigated by infrared spectoscopy and thermal analysis. Exposure of dental waxes to temperatures higher than 200 degrees C, particularly if it is repeated, may affect the composition and properties, resulting in inferior materials.