The detection of the risk for periodontitis, one of the major global burdens of disease, prior to noticeable signs and symptoms is of great importance especially in non-dental settings. Oral fluids, including gingival crevicular fluid (GCF), saliva and oral rinse, have received considerable critical attention in the field of periodontal diagnostics for their non-invasive features and rich sources of biomarkers associated with the biological process in periodontal tissues. Saliva and oral rinse are preferred for screening purposes in a chair-side test, while GCF provides more site-specific information and has higher technical requirements.~Matrix metalloproteinases (MMPs) are a family of key host proteinases that regulate cell-matrix composition and MMP-8 is the main type of collagenases of MMP family responsible for collagen degradation of the periodontal supporting tissues. A growing body of evidence have indicated that elevated MMP-8, especially active form of MMP-8 (aMMP-8), has been detected in oral fluids of periodontitis (Kc et al., 2020). Currently, a commercially available aMMP-8 point-of-care test (POCT) has been developed (U.S. Patent No. 10,488,415, 2019). A recent study has assessed the diagnostic utility of this aMMP-8 POCT using oral rinse samples and showed moderate accuracy for detecting periodontitis (Deng et al., 2021). So far, however, there is a paucity of research to assess the performance of aMMP-8 POCT using different oral fluid sampling methods.~The study aims: i)to compare the diagnostic accuracy of aMMP-8 POCT for the discrimination of periodontal health and disease(s) in oral rinse and saliva; ii) to compare the diagnostic accuracy of aMMP-8 POCT for the discrimination of periodontal health and disease(s) in oral rinse during the first sampling and re-sampling.~This study is a cross-sectional diagnostic study.The whole study procedures will comprise the collection of different oral fluid samples, the conduction of aMMP-8 POCT using these samples (index test), followed by a routine full-mouth periodontal examination (reference standard). The details of the sequential study events include: 1) collection of unstimulated whole saliva sample by spitting method; 2) the first-time sampling of oral rinse (pure oral rinse); 3) re-sampling of oral rinse; 4) conduction of aMMP-8 point-of-care test using saliva and oral rinse samples collected at different times; and 5) routing full-mouth periodontal examinations to establish clinical case diagnosis.
The application of point-of-care test with oral fluid-based biomarkers assisting in early-detection of gum disease is highly needed. Recently, a commercially available active Matrix metalloproteinase-8 (aMMP-8) point-of-care test (POCT) for detecting the risk of gum disease has been developed. Currently, there is a paucity of research to assess the performance of aMMP-8 POCT using different oral fluid sampling methods. This study will evaluate the accuracy of aMMP-8 POCT for discriminating periodontal health from disease in saliva and oral rinse.The information obtained from this study may help us understand better which sample is superior for the early detection of gum disease.