Evaluation of the effect of different irrigation activation methods on external temperature rise of the roots with simulated internal resorption cavities using infrared thermographic analysis

The aim of this study was to evaluate the outer surface temperature rise of the teeth with or without simulated internal resorption cavities during the activation of NaOCl with ultrasonics, diode laser, ER:YAG laser, and PIPS using an infrared thermal imaging camera. The root canals of 120 extracted single-rooted teeth were instrumented. Circular-shaped cavities simulating internal resorption defects were created on 60 instrumented teeth. The main groups were divided into six subgroups (n = 10): diode laser, ER:YAG laser, PIPS, passive ultrasonic irrigation (PUI), conventional needle irrigation, and control. The root surface temperatures during irrigation activation of the root canals were measured using an infrared thermal camera. The data were statistically analyzed using three-way ANOVA and Bonferroni tests. The maximum surface temperature rise values were observed at the middle thirds of the samples with simulated internal resorption, when diode laser was used as an irrigant activation method. Regardless of simulated internal resorption defects, using PIPS resulted in a temperature increase over the critical level (10 °C) at the coronal thirds of the teeth. ER:YAG laser, PIPS, and PUI caused statistically higher temperature rise at the middle root surfaces of the samples including internal resorption defects, compared to the middle thirds of samples without resorption (p < 0.001). Activation of the irrigants with laser systems during root canal treatment can increase the surface temperature of the roots over critical level, which may cause detrimental changes in periodontal tissues.