According to a randomized split-mouth clinical study published in the “Nigerian Journal of Clinical Practice”, the use of cold saline irrigation therapy (4°C) was found to be more effective than when used at room temperature (25°C) on the trismus (commonly called as lockjaw) after the surgery of mandibular third molars.

Removal of impacted wisdom teeth often triggers discomfort, swelling, and jaw stiffness post-surgery. Standard practice involves using room-temperature saline solutions (25°C) during extraction. In this study, saline solution at different temperatures was compared and assessed for postoperative pain, swelling, and occurrence of trismus after the surgical extraction of third molars.

A total of 18 patients with symmetrical mandibular impacted third molars were registered for this study. Each volunteer underwent irrigation on one side via a saline solution (0.9% isotonic sodium chloride) at 4°C (test group). On the other hand, the other side received irrigation via a saline solution at room temperature (25°C) (control group). On the 2nd, 4th and 7th days after the surgery, pain, trismus (lockjaw) and swelling on the face were evaluated.

The Mann-Whitney U-test was employed for pair-wise comparisons. For the group comparisons, the Wilcoxon signed-rank test was utilized. There were no profound variations between the study groups considering the intensity of pain and swelling. However, when it came to trismus, the maximum mouth opening observed with cold saline solution was notably superior compared to the room temperature irrigation throughout all post-surgical periods, as shown in Table 1:

Hence, using cold irrigation during impacted third molar extractions effectively reduces trismus when compared to irrigation at room temperature.