Influence of intracanal cryotherapy on postendodontic pain and interleukin-6 expression using different irrigation protocols: A randomized clinical trial

Abstract

Introduction: Cryotherapy is a new form of treatment, in which the body is exposed to cold temperatures. Hence, this study was aimed to evaluate the effect of intracanal cryotherapy on postendodontic pain and interleukin-6 (IL-6) expression in teeth with symptomatic apical periodontitis. Materials and Methods: Forty-eight single-rooted teeth in patients with symptomatic apical periodontitis were randomly divided into four groups based on the irrigation protocol. Group I (control): 5% sodium hypochlorite (NaOCl) at room temperature (RT) was used during instrumentation and final rinse. Group II: 5% cold NaOCl (2°C–5°C) was used during the root canal procedure. Group III: 5% NaOCl at RT during instrumentation, while the final rinse was 20 mL of 5% cold NaOCl (2°C–5°C). Group IV: 5% NaOCl at RT during instrumentation followed by 20 mL of cold saline (2°C–5°C). Postoperative pain score was recorded using a modified visual analog scale at 12, 24, 48, and 72 h and after 1 week. Paper point passing 2 mm beyond the apex was used to collect periapical fluid before, immediately after mechanical instrumentation, and after 1 week to characterize the mRNA expression of IL-6 using real-time polymerase chain reaction (PCR). Data were statistically analyzed. The significance level was set at P ≤ 0.05. Results: The control group showed the significant highest mean pain score (7), whereas experimental Groups II, III, and IV showed significantly lower mean pain scores with no significant differences in between (P > 0.05). Group II showed the lowest levels of IL-6 expression with no statistical significance between the experimental groups (P > 0.05). Conclusion: All irrigation protocols using intracanal cryotherapy resulted in lower postoperative pain levels and IL-6 expression than the control group.