Diagnostic Biomarkers of Periodontitis and Peri-Implantitis: The Past, the Present, the Future

In this narrative review we present our perspective on the past, present and future of periodontal and peri-implantitis diagnostic biomarkers. This topic parallels aetio-pathogenic research in that our understanding of the pathogenic, biological and biochemical mechanisms of these diseases is deeply entwined in the search for potential biomarkers of utility to diagnose them. Germane to this point is the marked success of bone-related molecules in saliva compared to cytokines and metalloproteinases in differentiating soft and hard tissue destruction. Despite these advances, translation into routine practice remains limited. Methodological heterogeneity, lack of standardised sampling protocols, biological variability, and insufficient longitudinal validation continue to impede progress. The roadmap ahead requires harmonised protocols, robust multicentre studies, clinically validated thresholds, and technologies that are rapid, affordable, and easily integrated into daily workflows. Biomarkers combined with other factors and interpreted by AI tools may be utilised in future to disclose current disease, predict future disease and aid in monitoring treated conditions: they may provide prognostic tools and have potential in epidemiological screening, particularly if readily available and easily accessible sample matrices such as saliva are used. Ultimately, the future of periodontal and peri-implant diagnostics lies in biologically informed, multi-modal assessment frameworks that complement traditional examination rather than replace it. As molecular technologies mature and AI-assisted personalised models evolve, biomarker-based diagnostics have the potential to transform early detection, risk prediction, and treatment monitoring-bringing us closer to precision periodontology and implantology. The salivary sample matrix is feasible for home use with utility for population screening, whereas the gingival and peri-implant crevicular fluid and the simple periodontal probe will continue to be invaluable in the analysis of localised disease.