Comparative Analysis of Temperature Changes with Preheated and Intracanal Heated Solutions and Ultrasonic Activation in Immature Teeth.

Introduction: The aim of this study was to examine the temperature changes on root canal and root surface in immature teeth with thin dentinal walls when irrigation solutions are preheated or intracanal heated, as well as the additional effects of passive ultrasonic irrigation (PUI) on these temperature changes.

Methods: Sixteen maxillary canine teeth were trimmed to a length of 20 mm and prepared to mimic immature teeth with an apical width of 1.3 mm by enlarging those using Gates Glidden burs. To measure temperatures inside the canal and on the root surface, one thermocouple was placed from the apex into the root canal, while the other thermocouple was positioned outside the root. Irrigation was performed by heating the irrigation solution with different methods (room temperature, preheated to 60°C, 5 sec intracanal heated, 20 sec intracanal heated), and PUI was applied after each method. Temperature changes occurring inside the root canal and on the root surface were recorded and subjected to statistical analysis.

Results: Using the irrigation solution preheated and intracanal heated resulted in a significant increase in both intracanal and root surface temperatures compared to using at room temperature (P < .05). The application of PUI significantly increased the temperature of the irrigation solution only at room temperature group (P < .05). None of the applications caused an increase in temperature on the root surface exceeding 10°C.

Conclusions: Applying PUI to heated solutions does not significantly increase the temperature in heating methods, but it does prolong heat retention in the canal by slowing down the cooling process. Although using preheated solution for 20 seconds results in higher intracanal temperatures, it should be noted that the solution cools rapidly within the canal. Short-term heating applications, such as 5 seconds, repeated frequently, can help maintain the high temperature during activation.