Microbiological and Metabolomic Analysis of Biomarkers for Grades A and B in Stage II Periodontitis

Periodontitis is a chronic inflammatory disease characterized by inflammation of the periodontal soft tissues and loss of alveolar bone. In the oral environment, subgingival microorganisms and salivary metabolites reflect the host's health status. This study aimed to understand periodontitis severity and progression rate by analyzing subgingival microflora and salivary metabolites to identify potential biomarkers. Fifty-three volunteers with stage II periodontitis were graded using the bone loss (%)/age index into two grades: 33 in grade A (< 0.25) and 20 in grade B (0.25-1.00). Using a case-control study, simultaneously analyzed biomarkers associated with the severity and rate of progression of periodontitis. The red complex, the orange complex, Campylobacter spp., uncultured Candidatus Saccharibacteria and metabolites such as 5-Aminovaleric acid, N1-Acetylspermine showed a significant positive correlation with periodontal clinical parameters. Furthermore, we identified four of the salivary differential metabolites (DL-Leucineamide, Dodecanedioic acid, L-Tyrosine methyl ester and Phenylpyruvic acid) that may serve as potential biomarkers for predicting the rate of periodontitis progression. These results showed that the red complex significantly correlated with periodontitis severity and influenced changes in salivary metabolites. Additionally, biomarkers indicating the progression rate were predominantly amino acid derivatives, confirming that interactions between microorganisms and metabolites may exacerbate periodontitis development.