The extracellular matrix in biofilms associated with peri-implantitis: evidence from experimental models and clinical investigations

The extracellular matrix (ECM) comprises structural and functional components that shape biofilm organization and influence microbial survival, virulence, and tolerance to host immune responses and antimicrobial interventions in peri-implantitis-associated biofilms. This narrative review summarizes current knowledge on ECM composition, organization, production, accumulation, and its relationship with biofilm structure and pathogenicity. A systematic literature search was conducted in PubMed, Web of Science, Embase, Scopus, and Lilacs. Studies evaluating ECM components in peri-implant biofilms were included. Of 4011 records identified, 34 studies were included: 22 in vitro, 4 in situ, 1 in vivo, and 7 clinical studies. In vitro evidence indicates that the biofilm matrix contributes to virulence, although differences in experimental models, growth conditions, implant surfaces, and ECM assessment methods limit comparisons and clinical extrapolation. In situ studies demonstrate that sucrose exposure, local pH gradients, and implant surface characteristics modulate ECM accumulation, biofilm architecture, and pathogenicity. Clinical studies further indicate that disease-associated biofilms are enriched in ECM and exhibit altered metabolic profiles. Overall, current evidence supports that ECM is an important contributor to peri-implant biofilm pathogenicity and highlights the need for molecular and longitudinal studies to clarify its functions and support the development of matrix-targeted therapeutic strategies.