Calcium hydroxide as an intracanal medication for postoperative pain during primary root canal therapy: A systematic review and meta-analysis with trial sequential analysis of randomised controlled trials

To evaluate the effectiveness of CH as an intracanal medicament compared to no dressing and / or other intracanal medicaments to control postoperative pain in patients with apical periodontitis requiring primary root canal therapy.We conducted electronic searches in PubMed, EMBASE, Scopus and Cochrane Library, Open Gray, and Google Scholar. A structured Population-Intervention-Comparison-Outcome of the review was as follows: Population: adults who presented with apical periodontitis requiring primary root canal therapy; Intervention: CH intracanal medicament; Comparison: no dressing/other intracanal medicaments; Main Outcome: Postoperative pain. We assessed the risk of bias using Cochrane criteria. Our outcome measures were intensity of pain on a validated scale reported as mean and standard deviation. We performed meta-analysis using the random-effects model. We rated the quality of evidence using GRADE.We included 18 studies with 1192 participants. The overall risk of bias was moderate. We found a significant improvement in postoperative pain at 24 hours in favor of CH over no intracanal medication (4 trials, n = 226: standardised mean difference: -0.71; [95% confidence interval: -1.38, -0.03]; P = .04; I2= 78%; moderate certainty evidence). Ledermix (Lederle Germany) (steroid-antibiotic) and chlorhexidine were significantly more effective than CH for controlling pain at 72 hours postprocedure (low certainty evidence). Silver nanoparticles were more effective than CH at 6 and 24 hours and combinations of CH with dexamethasone or lidocaine HCl were significantly more effective than CH alone at improving postoperative pain. Substantial heterogeneity limits the robustness of findings.Limited evidence suggests that CH may be an effective intracanal medicament for controlling interappointment pain. Combination therapies appear to be more effective than using CH alone. Further research assessing the comparative effectiveness of interventions for managing postoperative pain following root canal therapy is warranted.