Evaluation of the thermoplasticity of gutta-percha and Resilon® using the Obtura II System at different temperature...

To analyse the thermoplasticity of several endodontic filling materials using the Obtura II System at different temperature settings.

The following materials based on gutta-percha: Regular Obtura (OBT), Obtura Flow 150 (OBT F), Endo Flow (EDF), Odous (ODO) and the synthetic thermoplastic polymer material Resilon (RE) were heated using the Obtura II System at three temperature settings (140, 170 and 200 °C). Samples of the heated materials were placed on the sensor of a digital thermometer (THR-140; Instrutherm, São Paulo, Brazil) to determine their real temperature (RT) when the system was set at 140 °C (from 64.5 to 69 °C), 170 °C (from 73.8 to 77.5 °C) and 200 °C (from 83.6 °C for EDF and 100 °C for RE). Specimens (n = 30) were made by placing samples of each material in metallic ring moulds and compressing them between two glass slabs. After 24 h, specimens (n = 10) were heated at the different settings (RT) and submitted to compression under a 5-kg load. Plasticization was assessed by calculating the differences between the post-compression and initial diameters of each specimen. Data were submitted to anova and Tukey's test at 5% significance.

At 140 °C, Obtura Flow presented the highest thermoplasticity values and Regular Obtura, the lowest. At 170 °C, Obtura Flow and Resilon demonstrated greater plasticization. Resilon had the highest mean thermoplasticity values at 200 °C.

Thermoplasticity values were influenced both by the temperature settings on the Obtura II System and by the type of material analysed. Obtura Flow and Resilon had the highest mean thermoplasticity values.