Four-Year Longitudinal Epidemiological Study on the Association Between a Multi-Item Saliva Testing System and Oral...

Salivary Multi Test (SMT) is a device that can quickly and noninvasively measure seven parameters related to the oral environment using saliva as a sample: (1) bacteria that cause tooth decay, (2) acidity, (3) buffering capacity, (4) occult blood, (5) white blood cells, (6) protein, and (7) ammonia. This longitudinal study aimed to investigate the relationship between SMT and oral and gut microbiota in healthy general residents. After propensity score matching, 198 participants were included (low SMT group: 99 participants; high SMT group: 99 participants). We reclassified participants four years after the follow-up survey and compared the low- and high-SMT groups. The high SMT score group indicating a poor oral environment showed increased Olsenella in both the oral cavity and gut at the start of the survey and four years later. Oral Olsenella was strongly correlated with occult blood and protein levels. In contrast, a 4-year follow-up study demonstrated that changes in oral Olsenella were associated with occult blood changes. Conversely, changes in gut Olsenella were associated with changes in occult blood and protein. A poor SMT score has been shown to be linked to increased oral and gut Olsenella and improving the oral environment can improve the oral-gut microbial environment.