Postoperative pain following endodontic irrigation using 1.3% versus 5.25% sodium hypochlorite

What is it about?

Aim: This randomized, prospective, double-blind, clinical trial assessed the effect of 1.3% and 5.25% sodium hypochlorite (NaOCl) as irrigants on postendodontic pain and medication intake following root canal treatment of mandibular molars with non-vital pulps. Methodology: Three hundred and eight patients, each with one symptomatic or asymptomatic molar, were randomly assigned, using the permuted-block method, into two equal groups according to NaOCl concentration: 1.3% or 5.25% (n=154). For both groups, syringe irrigation was performed using a 27-gauge needle advanced into the canal to a depth of 3mm from the working length; 3 mL were used between every 2 consecutive instruments. All root canal treatments were carried out in two visits, with no intracanal medication, by trained postgraduate students. The canals were prepared using the Protaper Universal rotary system during the first visit. In the second visit 7days later, the same irrigant per group was used and the canal walls were reprepared with the final instrument before filling the canal using the modified single-cone technique with an epoxy resin-based sealer. Patients assessed their postoperative pain using the 0-10 numerical rating scale (NRS) immediately after instrumentation, 3h, 24h, 48h and 7d after the first visit and immediately following root canal filling. The incidence of rescue-medication intake (Sham or analgesic) was, also, recorded; patients received a sham capsule to be used first, but, if pain persisted, an analgesic was prescribed. Outcome data were analysed using Mann-Whitney U-test, Friedman's test, Wilcoxon's rank test and Chi2 (χ2 ) test. Relative risk reduction (RRR) and its 95% confidence interval (CI) were calculated for binary data. Results: The incidence and intensity of postoperative pain was significantly lower with 1.3% NaOCl than 5.25% NaOCl at all timepoints (p<0.05). Postoperative-pain intensity exceeded preoperative pain at 3h and 24h with 5.25% NaOCl only (p<0.05). The relative risk reduction in pain incidence was 38% (95% CI: 17%, 54%) immediately after instrumentation, 41% (95% CI: 31%, 49%) at 3h, 42% (95% CI: 32%, 51%) at 24h, 59% (95% CI: 45%, 69%) at 48h, 62% (95% CI: 27%, 80%) at 7d and 81% (95% CI: 68%, 89%) post root filling. RRR was 38% (95% CI: 1%, 61%) for sham intake and 69% (95% CI: 37%, 85%) for analgesic intake. Conclusions: Using 1.3% NaOCl was associated with less intense and less frequent postendodontic pain than 5.25% NaOCl in mandibular molars with non vital pulps treated in two visits. The incidence of pain was reduced by up to 60% within the week postinstrumentation and 80% post root canal filling and the rescue analgesic intake by about 70% on using 1.3% NaOCl compared to 5.25% NaOCl.

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Why is it important?

It is a randomized clinical trial assessing patient-relevant outcomes on a clinically-relevant research question.