Abstract
Abstract Postoperative pain following root canal treatment remains a common clinical problem, with the influence of engine‑driven endodontic file systems on pain being unclear. We conducted a PROSPERO‑registered systematic review and network meta‑analysis, reported in accordance with PRISMA and PRISMA‑NMA, to compare 24‑hour postoperative pain intensity across different file systems. Randomized clinical trials of adult patients undergoing primary root canal treatment reporting postoperative pain using validated scales were identified in PubMed, Scopus, Web of Science and Cochrane Library. Risk of bias was assessed with the revised Cochrane Risk of Bias Tool (RoB 2), and certainty of evidence was assessed with the Confidence in Network Meta‑Analysis (CINeMA) framework. Fifty‑one trials comparing 31 file systems, yielding 79 direct pairwise comparisons, were included. In symptomatic teeth, the Self‑Adjusting File and XP‑endo Shaper had the highest probabilities of producing lower postoperative pain, with mostly moderate certainty of evidence. In asymptomatic teeth, multiple file systems showed comparable efficacy, with substantial overlap in treatment rankings and overall certainty was low. There was no clear evidence of small‑study or publication bias. Within these limitations, Self‑Adjusting File and XP‑endo Shaper appear promising for reducing postoperative pain in symptomatic cases, whereas no file system shows clear superiority in asymptomatic teeth.