Impact of periodontal therapy on oral bacterial composition in individuals diagnosed with advanced periodontal disease.

Introduction. Negative changes in the microbial composition have been extensively studied in individuals with periodontal disease.Gap Statement. The changes in the oral microbiota after treating this disease are still unknown.Aim. We sought to elucidate the distinctive traits of salivary microbiota in individuals displaying healthy gums and those with severe periodontitis (SP) and examine the influence of periodontal therapy.Methodology. Periodontal pocket depths were examined to determine disease severity. The presence and quantity of oral Helicobacter pylori (associated with periodontal disease) were determined. Sequencing of 16S ribosomal DNA and bioinformatic analyses were performed to assess oral bacterial compositions in patients.Results. Sequencing analysis of 16S ribosomal DNA revealed a significant reduction in the abundance of operational taxonomic units (OTUs) and Chao1 and Abundance coverage-based estimator(ACE) indices in the oral cavities of individuals with SP compared to those of the healthy controls. However, these parameters showed significant recovery after appropriate treatment severe periodontitis after treatment (TSP). Additionally, the levels of harmful Bacillales and Spirochetes significantly increased, whereas the presence of beneficial Euryarchaeota significantly decreased in the SP group. The TSP group exhibited considerably augmented abundances of Burkholderiaceae and Veillonella, while noteworthy reductions in the pathogenic microbiota (Clostridia, Fusobacteria and Spirochaetes) were noticed compared to those of the SP group. Functionally, these modified OTUs were extensively implicated in 41 metabolic pathways.Conclusion. Our study demonstrates that nonsurgical periodontal therapy can effectively reduce the diversity of the oral microbiota, thereby potentially enhancing the treatment efficacy in patients with periodontal disease.