Temperature change within gutta-percha induced by the System-B Heat Source

Aim: This study evaluated the temperature change within gutta-percha during the vertical compaction technique performed with a System-B Heat Source. Methodology: Extracted human teeth were prepared, and divided in two equal groups depending on the apex diameter (group 1: 0.20-0.25 mm and group 2: 0.30-0.35 mm). Teeth were root treated with a combination of step-back and coronal flaring instrumentation using Gates Glidden burs and hand stainless steel K- and H-files. Two thermocouples were connected to the outer surface of the root the first one was placed 2 mm apically from cement-enamel junction (CEJ) (point C); and the second one 1.5 mm from the apex (point A). The instrumented canals were filled with size F gutta-percha cones. All teeth were then immersed in a thermostatic bath at a constant temperature of 37°C and warm vertical compaction was performed using a System-B Heat Source. ΔT values were recorded by means of a digital thermometer connected to the thermocouples. Results: Increments of temperature (ΔT) recorded In point A revealed a mean value of 0.5 ± 0.5°C for group 1 and 0.9 ± 1.1°C for group 2; ΔT values recorded at point C gave a mean value of 4.1 ± 1.7°C for group 1 and 3.9 ± 1.81°C in group 2. No statistical difference was found between the groups, whilst a difference was present between the measurements at points A and C (P < 0.01). Conclusions: The use of the System-B Heat Source on root canals maintained at a constant body temperature by a thermostatic bath revealed that the increase of temperature of the gutta-percha at the apical third of the canal was negligible and that the compaction of the mass of the gutta-percha close to the apex was performed at body temperature. Minor changes in temperature of the outer surface of the root canals occurred, suggesting no danger for the periradicular tissues.