Effects of sodium hypochlorite with different concentration on endodontic postoperative pain: a systematic review and meta-analysis of randomized controlled trials

Abstract

AbstractBackgrounds: Sodium hypochlorite (NaOCl) has been the most widely used chemical auxiliary substance in endodontics owing to its effective antimicrobial action and excellent tissue-dissolving properties. To date, the ideal concentration of NaOCl has not been established, since potential complications are still controversial. NaOCl is routinely used in endodontics, the aim of the present study is to answer the following question: Does the concentration of NaOCl have effects on postoperative pain in endodontic treatment of permanent teeth? Methods Electronic databases, including PubMed, EMBASE, Web of Science and Cochrane Library, were searched for randomized controlled trials published from their start dates to March 2021 using strict inclusion and exclusion criteria, and reviewed following PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines. Only randomized controlled trials that compared the effects of NaOCl with different concentrations on endodontic postoperative pain during chemomechanical preparation of permanent teeth with endodontic infection were included. Two reviewers respectively assessed the eligibility for inclusion, extracted data and assessed the quality using the risk of bias tool. Results From 1638 studies that resulted from the initial search, 22 articles were included for full-text appraisal; five articles met the inclusion criteria for quantitative synthesis. A single meta-analysis was performed to compare the effects of NaOCl with different concentrations on endodontic postoperative pain in endodontic treatment of permanent teeth. The forest plot of endodontic postoperative pain indicated that there was no difference in incidence of endodontic postoperative pain between low concentration and high concentration of NaOCl (odd ratio [OR]: 0.60; 95% confidence interval [CI], 0.20–1.74; P = 0.34). Conclusions This review has been the first analysis to compare the incidence of endodontic postoperative pain after irrigation of NaOCl between low concentration group and high concentration group of permanent teeth so far. Based on the present limited evidence, the study suggested that there was no difference in incidence of endodontic postoperative pain between low concentration and high concentration of NaOCl in permanent teeth with endodontic infection. Trial registration: PROSPERO (CRD42021241829).