Effect of low-temperature intracanal sodium hypochlorite on root surface temperature reduction and organic tissue dissolution: an in vitro study

INTRODUCTION: This study aimed to evaluate the effect of low-temperature intracanal sodium hypochlorite (NaOCl) irrigation on root surface temperature reduction and its ability to dissolve organic tissue. METHODS: Extracted mandibular premolars were accessed and instrumented. Final irrigation protocols with NaOCl, at two different temperatures: room temperature (control) and 2.5 °C (experimental), were applied. Initial and the lowest root surface temperatures were recorded using a digital thermometer. Organic tissue dissolution was assessed using glass capillaries, filled with catgut, attached to 3D-printed maxillary incisors exposed to the same irrigation protocols. Data was statistically analyzed. RESULTS: Low-temperature NaOCl irrigation led to a significantly greater reduction in root surface temperature compared to room temperature NaOCl (p < 0.05). Both irrigation protocols showed similar organic tissue dissolution, with no significant difference between them (p > 0.05). CONCLUSION: Intracanal irrigation with low-temperature NaOCl effectively reduced root surface temperature while maintaining its organic tissue dissolution capacity. CLINICAL RELEVANCE: The use of cold sodium hypochlorite represents a simple and effective intracanal cryotherapy approach that may help to minimize postoperative inflammation while preserving the chemical efficacy of the irrigation during endodontic treatment.