The Effect of Storage Temperature on Mechanical Properties of GuttaPercha and Resilon

Objectives: To compare the mechanical properties of Resilon and gutta-percha cones after storing at three different temperatures. Materials and Methods: One-hundred standardized size 40/02 gutta-percha cones and 100 Resilon cones were randomly divided into four groups. The first group of the materials were tested immediately after receipt as the control group. The other three were stored in their packages at -12C, 4± 1C and 22± 2C for three months. Then, obturating cones were loaded by a tensile force at the rate of 5mm/min. Physical in- tegrity of gutta-percha and Resilon cones were also evaluated according to ISO6877. The data were analyzed by one-way analysis of variance, post hoc and t-test. A p- value <0.05 was considered significant. Results: The elasticity modulus of gutta-percha reduced significantly after three months storage at -12°C, while storage at 4±1C and22± 2C had no effect on its modulus of elasticity. In addition, the tensile strength of gutta-percha did not change after three months of storing. The modulus of elasticity of Resilon reduced signifi- cantly in all storage conditions; however, its tensile strength did not change. The stor- age conditions did not have a significant effect on the elongation rate of guttapercha and Resilon. Eighty percent of guttapercha cones lost their physical integrity after storage in 4 °±1C and 22±2°C. However, storage conditions had no impact on the physical integrity of Resilon cones. Conclusion: Storing guttapercha at -12C can benefit its properties, while keeping Resilon at both refrigerated and room conditions can preserve its mechanical proper- ties.