Abstract: PURPOSE: To investigate the effect of normal saline irrigation at different temperatures on postoperative complications during the extraction of impacted mandibular third molars. METHODS: A total of 21 patients who underwent extraction of bilateral impacted mandibular third molars at Hefei Stomatological Hospital from February 2021 to June 2025 were enrolled in this study. A randomized self-controlled design was adopted, where the bilateral impacted teeth were divided into an experimental group (irrigated with 4 ℃ low-temperature normal saline during surgery) and a control group (irrigated with 26 ℃ room-temperature normal saline during surgery). All patients received staged extraction of bilateral impacted teeth, with the two surgeries serving as mutual controls. The visual analog scale (VAS) was used to record the pain scores at 0.5, 2, 6, 12, 24 and 72 hours postoperatively. Meanwhile, the operation time, the degree of edema at 72 hours postoperatively, the dosage of analgesics, mouth opening degree, postoperative bleeding, and the incidence of dry socket were recorded. RESULTS: The VAS scores at 2 and 6 hours postoperatively and the degree of edema at 72 hours postoperatively in the experimental group were significantly lower than those in the control group (P<0.05). No significant differences were found between the two groups in operation time, analgesic dosage, mouth opening degree, postoperative bleeding, the incidence of dry socket or VAS scores at other recorded time points (P>0.05). CONCLUSIONS: Irrigation with 4 ℃ low-temperature normal saline during minimally invasive extraction of impacted mandibular third molars can significantly alleviate postoperative pain at 2 and 6 hours and edema at 72 hours, which is worthy of clinical application.

Key words: Normal saline irrigation, Impacted mandibular third molar, Minimally invasive tooth extraction, Postoperative complications, Pain, Edema