From Stability to Dysbiosis: Ecological Profiling of Subgingival Biofilms in Costa Rican Adults with Periodontal Health and Disease-A Pilot Study

This pilot study characterized the subgingival microbiota in Costa Rican adults with and without periodontitis, using 16S rRNA gene sequencing and ecological diversity analysis. The study sample consisted of 20 participants, including 10 with periodontal health and 10 diagnosed with periodontitis, from whom subgingival samples were collected for DNA extraction and sequencing of the V3-V4 region. Amplicon sequence variants (ASVs) were analyzed to assess alpha and beta diversity, identify indicator taxa, and explore microbial co-occurrence patterns. Rarefaction curves indicated adequate sequencing depth. Although alpha diversity indices were higher in the periodontitis group, the differences were not statistically significant (p>0.05), but showed moderate effect sizes. Beta diversity revealed significant differences between groups (PERMANOVA, p<0.05), with greater dispersion observed in the periodontitis group (Betadisper, p<0.05). P. gingivalis and T. denticola were identified as indicator taxa for the periodontitis group. Microbial networks showed distinct ecological organization between groups. These findings support the ecological model of dysbiosis and provide preliminary evidence on the subgingival microbiota in the Costa Rican population, laying the groundwork for future longitudinal studies on the progression or resolution of periodontal disease.