Development of a Quantitative Detection System for Porphyromonas gingivalis Based on Immunochromatography

Background: Porphyromonas gingivalis is the principal bacterial species implicated in the pathogenesis of periodontitis. Despite its central role, direct detection of periodontopathic bacteria is not routinely performed in dental clinics. Although test kits using monoclonal antibodies against P. gingivalis have been reported, no practical chairside method has yet been established. Objectives: In this study, we developed an immunochromatography system that enables rapid and quantitative detection of P. gingivalis within 10 min. Methods: We evaluated the performance of the developed immunochromatography system and its dedicated measurement reader. Results: The kit demonstrated a minimum detection limit of 2.6 × 10⁴ CFU/mL and maintained detection capability across fimbrial types I and II. The dedicated reader showed strong correlations with a reference reader (R² = 0.9921) and visual color chart evaluation (R² = 0.9347). High intra- and inter-device precision was observed, with coefficients of variation less than 0.6%. Although the presence of 2% whole blood interfered with visual interpretation, other oral substances, including toothpastes and mouthwashes, did not significantly affect the assay performance. Conclusions: Collectively, these findings indicate that the developed system may serve as a rapid and reliable chairside tool for quantitative detection of P. gingivalis, with potential utility in the diagnosis and management of periodontitis and related systemic conditions.