Influence of activation mode and preheating on intracanal irrigant temperature.

This ex vivo study assessed the effectiveness of two activation modes to increase the intracanal temperature of 5.25% NaOCl solution and the time for a preheated-irrigant to return to its initial temperature. Ten single-rooted extracted human teeth were used. Thermocouples were adapted to the root surface and the temperature was registered following two activation modes: ultrasound (US) and thermal. Furthermore, a preheated-solution (45°C/60°C) was flushed into root canal to test the time needed to return to its initial temperature. Data were analysed using two-way ANOVA and Tukey's post-hoc tests (P = 0.05). Statistical analysis showed differences between the activation modes. US and thermal activation increased from 37 to 40.4°C and to 62.8°C respectively in 60 s. Time for preheated-irrigant to return to its initial temperature was longer for 60°C. Preheating irrigant at 60°C and using thermal activation to keep it warm may represent a further step of the irrigation protocol.