Heat Transfers to Periodontal Tissues and Gutta-percha During Thermoplasticized Root Canal Obturation in a Finite Element Analysis Model

Objectives: The aim of this study was to measure the temperature distributions on the periodontal ligament and apical gutta-percha during thermal obturation with different plugger activation time.

Study Design: The multirooted model of mandibular first molar development and root canal treatment were performed by finite element analysis. The apical thirds of canals were obturated by continuous-wave condensation technique, with 3 seconds and 4 seconds of activation time. The remainder was backfilled with injected gutta-percha in 2 segments (Obtura II).

Results: The highest temperatures on the periodontal ligament reached 46.914 degrees C and 48.887 degrees C, in the "dangerous zone" between the root canals, when activation times were 3 seconds and 4 seconds, respectively. The greatest temperature rise within the apical gutta-percha was only 0.859 degrees C.

Conclusion: With 3 seconds of activation, the temperature elevation reached almost 47 degrees C, so one should be careful not to extend the activation time beyond 3 seconds, which is clinically difficult to control. The apical gutta-percha temperature was always below the desired level to achieve proper thermoplasticity.