Integration of periodontal pathogens and inflammatory mediators in saliva as biomarkers for periodontitis

Periodontitis pathogenesis is driven by oral microbiome dysbiosis and dysregulated host immune responses. This cross-sectional study characterized salivary microbiome and inflammatory mediator profiles to identify candidate biomarkers distinguishing periodontal health from periodontitis (PD) using hyperplex PCR, multiplex assay and exploratory machine learning.

Stimulated saliva samples from 57 participants (28 periodontally healthy, 29 with PD stage III/IV) were collected and analyzed using Hyperplex PCR (simultaneously amplifying multiple targets in a single assay) for oral bacteria and a multiplex immunoassay including 37 inflammatory mediators. Random forest modeling explored the discriminatory performance of individual and combined biomarkers.

Individuals with PD stage III/IV showed elevated relative abundance of Filifactor alocis, Fretibacterium spp., Parvimonas micra (P < 0.05) compared to periodontally healthy individuals. Among determined inflammatory mediators, the levels of Chitinase 3-like 1, sIL-6Rβ, sIL-6Rα, IL-19, pentraxin-3, sTNF-R1 and TWEAK were elevated in PD stage III/IV. Exploratory modeling identified Fretibacterium spp. as the strongest individual discriminator (AUC = 0.82), a performance that was not improved by two- or three-marker combinations incorporating additional bacteria or inflammatory mediators.

In exploratory unadjusted analyses, salivary Fretibacterium spp. showed the highest discriminatory performance (AUC = 0.82), although this association was not statistically significant after adjustment for age, smoking, and cardiovascular disease. These exploratory findings require further validation in larger, diverse cohorts to assess their potential clinical utility.