Activated irrigation systems and postoperative pain after single-visit root canal treatment: A network meta-analysis

To evaluate the comparative effect of irrigation activation systems on postoperative pain after single-visit nonsurgical root canal treatment using a systematic review and network meta-analysis.

A systematic search of PubMed/MEDLINE, Embase, Cochrane CENTRAL, and clinical trial registries was conducted in accordance with PRISMA-NMA recommendations. Randomized and quasi-randomized clinical trials evaluating postoperative pain after single-visit root canal treatment with different irrigation activation protocols were considered eligible. The primary outcome was 24-h postoperative pain intensity. Secondary outcomes included pain at other postoperative time points, analgesic intake, flare-up incidence, and categorical pain severity. Risk of bias was assessed using RoB 2 and ROBINS-I, and certainty of evidence was assessed using the GRADE framework. A frequentist random-effects network meta-analysis was performed using standardized mean differences.

Seven studies with extractable continuous 24-h postoperative pain data contributed to the primary network meta-analysis. Compared with conventional irrigation, laser-activated irrigation showed the largest reduction in 24-h postoperative pain (SMD = -1.21; 95% CI: -1.86 to -0.55; P-score = 0.993), followed by passive ultrasonic irrigation (SMD = -0.39; 95% CI: -0.86 to 0.08; P-score = 0.520) and sonic activation (SMD = -0.32; 95% CI: -0.85 to 0.22; P-score = 0.429). Conventional irrigation had the lowest P-score (0.058). The certainty of evidence ranged from low to moderate, with downgrading mainly due to imprecision, clinical heterogeneity, and limited direct evidence for some comparisons. Risk-of-bias assessment identified predominantly low-risk randomized trials, although some studies raised concerns related to deviations from intended interventions, incomplete blinding, or incomplete outcome reporting.

Laser-activated irrigation may reduce 24-h postoperative pain compared with conventional irrigation after single-visit root canal treatment. The effects of passive ultrasonic irrigation and sonic activation were less certain. Treatment rankings should be interpreted alongside effect estimates, confidence intervals, risk of bias, clinical heterogeneity, and certainty of evidence rather than as independent evidence of clinical superiority.

Irrigation activation may influence early postoperative pain after single-visit root canal treatment. Current evidence suggests a potential short-term pain-reduction benefit with laser-activated irrigation, but the certainty of evidence remains limited. Clinicians should interpret treatment hierarchy cautiously and consider feasibility, cost, case complexity, and patient-related factors when selecting irrigation activation protocols.