Prognostic Impact of Microbiome Dysbiosis: A Prospective Study.

AIMS To determine the relationship between microbiome dysbiosis indices and biofilm immunogenicity and their prognostic implications on periodontal treatment response. MATERIALS AND METHODS Thirty periodontally healthy controls and 30 periodontitis cases (stage III) were recruited. Cases received non-surgical periodontal therapy (NSPT), and their treatment response at 6 months was evaluated using a treat-to-target endpoint (≤ 4 sites with probing depths ≥ 5 mm). Pooled subgingival biofilm samples were obtained from controls and cases. The V3-4 hypervariable region of the 16S rRNA gene was sequenced and two compositional indices (subgingival microbiome dysbiosis index, SMDI, and dysbiosis ratio, DR) were calculated. Nuclear factor kappa-B (NF-κB) activation elicited by biofilm samples in monocytic reporter cells was quantified to assess biofilm immunogenicity. RESULTS SMDI, DR and biofilm immunogenicity were highly diagnostic for periodontitis (area under curves [AUC] > 0.90, p < 0.001). Among periodontitis cases, all three microbial parameters were significantly reduced after NSPT (p < 0.001). Cases achieving the treat-to-target endpoint had lower pre-treatment SMDI and biofilm immunogenicity (p < 0.05) and different microbial recolonization patterns from poor responders. Both measures predicted treatment response (AUC of 0.767 and 0.835, respectively, p < 0.05). CONCLUSION Subgingival biofilm dysbiosis quantified using SMDI and biofilm immunogenicity was diagnostic of periodontitis and predictive of NSPT outcomes.