Effect of Intracanal Cryotherapy on Postoperative Pain

Introduction: Since 1960, cryotherapy, involving the application of cold, has been used in various fields of medicine for pain treatment. Cold application induces three main physiological tissue responses: a decrease in metabolic activity, a reduction in blood flow, and the inhibition of neural receptors in the skin and subcutaneous tissues. Consequently, cryotherapy slows down neural signals and reduces the release of chemical mediators responsible for pain. Recently, the use of cryotherapy in root canal treatment, in the form of cold saline irrigation, has been investigated in several randomized controlled trials. The aim of this study is to evaluate the effect of cold saline irrigation as a final irrigant on postoperative pain following the biomechanical preparation of root canals in patients undergoing non-surgical retreatment. Method: Sixty single-rooted, single-canal teeth requiring non-surgical root canal retreatment were randomly assigned to two groups (n = 30): a cryotherapy group and a control group. All the treatments were completed during a single visit. Protaper Universal Retreatment files (D1, D2, and D3) were used for the removal of gutta-percha and root canal preparation, and irrigation was performed using 2.5 % NaOCl and 17% EDTA. The cryotherapy group had a final irrigation temperature of 2.5 °C for 5 min before root canal obturation, whereas the control group received irrigation at room temperature. All patients will be asked to record their postoperative pain levels on VAS scales at 6, 12, and 24 hours, and at 2, 3, and 7 days after treatment. Patients will be asked to rate the pain they experience during the 7-day postoperative period on a scale from 0 to 10. Statistical analysis was performed using the Chi-Square test, Mann-Whitney test, and Independent Samples test, with the significance level set at 0.05.