Young's modulus of warm and cold gutta-percha.

The purpose of this study was to evaluate the Young's modulus of cold and warm gutta-percha. Rods of gutta-percha. Specially designed by three companies were tested at 20 degrees C and 55 degrees C with a tensile testing machine. The Young's modulus, the yield strength and the percentage of deformation were automatically recorded. There was a statistically significant difference, for the three criteria, between the cold and warm gutta-percha. Warm gutta-percha presented a Young's modulus 100 times smaller, a yield strength 2 times smaller but a percentage of permanent deformation 10 times higher than cold gutta-percha. Gutta-percha Hygenic presented the best characteristics.