Efficacy of adjunctive hydrogel therapy in the management of peri‑implant diseases: A systematic review

Peri‑implant diseases remain a critical challenge in implant dentistry, and adjunctive hydrogel therapy has emerged as a potential strategy to enhance conventional non‑surgical management. The present systematic review assessed the efficacy of adjunctive hydrogel therapy, compared with conventional non‑surgical therapy or other local adjuncts, in the management of peri‑implant diseases, focusing on clinical, microbiological and radiographic outcomes reported in randomised controlled trials (RCTs). Conducted in accordance with the PRISMA 2020 guidelines and registered in PROSPERO (CRD420251163004), a search was performed on the PubMed, Scopus, Web of Science and Cochrane CENTRAL databases for studies published from 2011 to September, 2025, supplemented by hand‑searching, grey‑literature review and reference screening. Only human RCTs evaluating hydrogel‑based adjuncts were eligible. Subsequently, two reviewers independently performed study selection, data extraction and risk‑of‑bias assessment using Cochrane RoB 2, and the certainty of evidence was rated using GRADE. A total of six reports from five RCTs (two reports sharing one peri‑implantitis cohort), published between 2020 and 2025, were included. The hydrogels evaluated were 15% ozonated sunflower‑oil hydrogel, 1.2% atorvastatin gel, a bio‑adhesive antiseptic gel and 0.8% high‑molecular‑weight hyaluronic acid (HA), compared with 1% chlorhexidine gel, placebo/excipient gel, or mechanical debridement alone. Ozonated sunflower‑oil hydrogel exhibited greater improvements in soft‑tissue inflammation (bleeding on probing, bleeding score and suppuration) than chlorhexidine, whereas atorvastatin gel improved the clinical attachment level and pain on probing without a consistent reduction in bleeding on probing, and HA additionally reduced crevicular IL‑1β and shifted the submucosal microbiome towards a less pathogenic profile. The bio‑adhesive antiseptic gel and chlorhexidine achieved comparable clinical outcomes in their respective trial, though chlorhexidine caused soft‑tissue and prosthetic staining. Adjunctive hydrogels appear to provide promising, although modest and inconsistent, benefits over mechanical debridement or chlorhexidine, mainly for inflammatory parameters, with very low to moderate certainty of evidence. Heterogeneity in formulations, protocols and follow‑up durations, along with reliance on small single trials, limits firm conclusions. Standardised, longer‑term RCTs are warranted to confirm these preliminary findings.