A dynamic microcosm biofilm model for root carious-like lesion development: analysis of demineralization and microbiological characterization

This study investigated the multifunctional oral cavity simulator (MOCS) in terms of microbial composition, functional profile, and dentin root demineralization. Microcosm biofilms were grown on dentin using human saliva for 4, 7, and 14 days, with exposure to sucrose and a mucin-enriched medium. Biofilms were analyzed for microbial viability and composition through CFU count and 16S-rRNA gene sequencing. Demineralization was quantified by percentage surface hardness change (%SHC), mineral loss (ML), and lesion depth (LD). The results showed microbial viability at all time points. After 7 days, aciduric/acidogenic and proteolytic organisms increased in abundance. The functional profile reflected the oscillations in microbial composition. No significant differences in %SHC, ML, or LD were observed across the time points. Carious lesions exhibited 60-70% SHC and 125-200 µm depth. MOCS was able to induce root carious lesions as result of microcosm biofilm metabolic activity, indicating its potential use in preclinical studies on root dentin caries.