Prognosis of Periapical Lesions Treated by Activated Disinfection (PUI, Laser) Without the Use of Systemic Antibiotics: Systematic Review and Meta-Analysis

Background/Objectives: Activated irrigation techniques improve intracanal disinfection, but their impact on the clinical and radiographic healing of apical periodontitis remains unclear. This systematic review and meta-analysis evaluated the efficacy of passive ultrasonic irrigation (PUI) and laser-assisted irrigation (LAI), without adjunctive systemic antibiotics, on periapical healing compared with conventional irrigation in adult patients. Methods: Following PRISMA guidelines and prospective registration in PROSPERO (CRD420261413401), PubMed, Scopus, Embase, and Web of Science were searched up to February 2026. Randomized controlled trials (RCTs) involving adults with apical periodontitis comparing PUI or LAI against conventional syringe irrigation—with a minimum of 6 months follow-up—were included. Risk of bias was assessed using RoB 2, evidence certainty via GRADE, and a random-effects meta-analysis calculated pooled odds ratios (ORs) and 95% confidence intervals (CIs). Results: Of 1115 records identified, five randomized controlled trials involving 451 teeth fulfilled the eligibility criteria and were included in the qualitative synthesis and quantitative meta-analysis. Activated irrigation significantly increased periapical healing probability compared with conventional irrigation (OR = 2.25; 95% CI: 1.29–3.93; p = 0.004), with no statistical heterogeneity (I2 = 0%). Subgroup analyses showed significant benefits for both PUI (OR = 1.95; 95% CI: 1.08–3.54) and LAI (OR = 6.77; 95% CI: 1.63–28.12). The overall certainty of evidence was moderate due to risk of bias concerns. Conclusions: Activated irrigation techniques (PUI and LAI) were significantly associated with improved clinical and radiographic healing of apical periodontitis compared with conventional irrigation alone. Enhanced intracanal disinfection contributes to a more predictable resolution of periapical lesions without adjunctive systemic antibiotics. Further high-quality RCTs with standardized protocols and long-term CBCT-based follow-up are required to confirm these findings.