Comparing Ultrasonically Activated Irrigation and Laser-Activated Irrigation for Postoperative Pain Reduction in Endodontics: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

Introduction: This systematic review and meta-analysis evaluate the effects of ultrasonically activated irrigation (UAI) and laser-activated irrigation (LAI) on postoperative pain following root canal treatment (RCT).

Methods: An extensive search of the literature was performed using MEDLINE, Web of Science, Embase, and the Cochrane Library from January 2000 to March 2025. Eligible randomized controlled trials (RCTs) comparing UAI with LAI and reporting postoperative pain outcomes at multiple postoperative time on the visual analog scale were included. The included RCTs were thoroughly evaluated for potential risk of bias and overall quality of evidence, and their data were pooled and analyzed using a random-effects model.

Results: Seven RCTs (n = 490 teeth, 30 comparisons) were meta-analyzed, showing that LAI significantly reduced postoperative pain compared to UAI (standard mean difference [SMD] = -0.58; 95% CI: -0.94 to -0.22; P = .0016). Subgroup analysis highlighted the greatest pain reduction at 24-48 hours (SMD = -1.00), especially with pulsed Er: YAG lasers (PIPS: SMD = -1.10; SWEEPS: SMD = -1.57), while diode lasers showed no significant effect (SMD = 0.03). Sensitivity analyses supported the reliability of these findings.

Conclusions: LAI provides a statistically and clinically meaningful reduction in postoperative endodontic pain compared to ultrasonic activation, with the most pronounced effects observed between 24- and 48-hours post-treatment. Among laser types, pulsed Er: YAG modalities-especially SWEEPS-demonstrated the strongest analgesic benefit.