Young's modulus of warm and cold gutta‐percha

Abstract

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.

Fracture mechanics analysis of vertical root fracture from condensation of gutta-percha

“…Table 2 lists the elastic constants used. The gp is assumed elastic-perfectly plastic with yield stress s 0 ¼16 MPa (Friedman et al, 1975;Camps et al, 1996) and a post-yield behavior characterized by von-Mise's flow rule with incremental plasticity and isotropic hardening. For simplicity, the root and its canal are assumed conical, with local mean radius R l ¼R 0 þ0.043l.…”

An ex vivo comparison of three different gutta‐percha cones when compacted at different temperatures: rheological considerations in relation to the filling of lateral canals

“…However cold gutta-percha cannot flow. When a compaction force is applied on cold gutta-percha, the relationship between stress (Mpa) and deformation (%) can be represented by a curve (Camps et al 1996). The first part of the curve is straight: there is a linear relationship between stress and deformation.…”

“…The percentage of deformation is the loss of length in percentage, necessary to reach a permanent deformation. The cold gutta-percha presents a high yield strength and a small percentage of deformation, whilst warm gutta-percha, on the contrary, presents a small yield strength and a high percentage of deformation (Camps et al 1996). When cold lateral condensation is used, the spreader induces both elastic and plastic strain (Camps et al 1996).…”

“…The cold gutta-percha presents a high yield strength and a small percentage of deformation, whilst warm gutta-percha, on the contrary, presents a small yield strength and a high percentage of deformation (Camps et al 1996). When cold lateral condensation is used, the spreader induces both elastic and plastic strain (Camps et al 1996). But when the spreader has been retracted to allow the insertion of accessory cones, the reversible elastic strain obviously vanishes.…”

Intracanal temperature rise evaluation during the usage of the System B: replication of intracanal anatomy

“…Furthermore, a study in which Young's modulus of warmed GP was evaluated, it was concluded that it was necessary for the plugger to be introduced apically to obtain permanent deformation. The high percentage of deformation and the low yield strength of GP mean that it is easily compacted but the plugger must be introduced apically as the permanent deformation is undergone only after 50% reduction in volume is enhanced (Camps et al. 1996).…”