Effect of aging on the mechanical properties of hand-rolled gutta-percha endodontic cones.

This study examined the effect of storage, for periods varying up to 24 weeks and at temperatures from -12 degrees C. to 50 degrees C., on the compression, tension, torsion, and bend properties of size 100 hand-rolled gutta-percha cones. All of the properties changed during storage, with the largest changes occurring at the highest temperatures, the smallest changes occurring at the lowest temperatures, and the greatest rate of change occurring during the initial 40- to 60-day storage period. All of the cones tested were subjectively found to be clinically usable. Since ideal characteristics or standards for mechanical properties are nonexistent, assessment of the changes is speculative and arbitrary. The condition of cones at which clinicians decide they are unusuable also varies widely. Continual study of this problem is indicated and important.