Saliva offers a non⍰invasive, low⍰cost, and patient⍰friendly matrix for biomarker discovery. Affinity⍰based proteomic technologies such as the Proximity Extension Assay (PEA) are increasingly being adopted for large⍰scale biomarker studies, yet they remain underexplored in saliva. This study applied the Olink Explore High⍰Throughput (HT) PEA platform to profile approximately 5,400 proteins in saliva samples collected from donors representing periodontal health, gingivitis, advanced periodontitis (baseline and 3⍰months post⍰treatment), and edentulism.

Saliva from 68 donors was analysed, and all samples passed Olink’s quality⍰control procedures, with only 17 of 5,416 assays failing. Forty⍰one percent of proteins were detected above the limit of detection, demonstrating substantial assay sensitivity in this biofluid. Principal component analysis revealed clear compositional differences between clinical groups, with post⍰treatment periodontitis samples clustering more closely with health than baseline disease. Pairwise group comparisons identified hundreds of differentially abundant proteins, with consistently more proteins increased than decreased relative to health.

This study demonstrates, for the first time, that Olink HT can robustly measure thousands of proteins in saliva with high data quality and biologically meaningful discrimination between periodontal states. The platform’s minimal sample⍰volume requirements and scalability present strong potential for future saliva⍰based biomarker discovery and translational research.

Monique Stoffels and Matthias Born are employees of Philips Oral Healthcare and have contributed to the design and analysis of the study.

This study was funded by Philips Oral Healthcare

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

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The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

Ethics committee of Durham & Tees Valley 1 NHS Research gave ethical approval for this work ref. 09/H0905/49

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I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

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All data produced in the present study are available upon reasonable request to the authors