Mechanical biofilm disruption causes microbial and immunological shifts in periodontitis patients

Abstract

Periodontitis is characterized by subgingival biofilm dysbiosis, inflammation and tissue destruction. Current treatment involves mechanical biofilm disruption known as non-surgical periodontal therapy (NSPT). This study sought to characterise the impact of treatment on microbial diversity and overall community, and the parallel impact on host inflammation in the oral cavity. Fourty-two periodontitis patients were included in this study, with periodontal clinical parameters, subgingival plaque and saliva samples collected at baseline and 90 days after treatment. Salivary cytokines were quantified, and subgingival plaque was analysed using 16S rRNA sequencing. After treatment, there were marked health-associated alterations in microbial composition and diversity, including differential abundance of 42 genera and 61 species. These changes were accompanied by substantial clinical improvement (pockets ≥ 5 mm, 27.50% to 9.00%, p < 0.001) and a decrease in salivary IL-1β (p < 0.001)—a putative marker of periodontal inflammation. Despite significant reductions in disease associated anaerobes, several genera (Fusobacterium, Prevotella, Tanenerella, Treponema) remained present and formed a distinct subnetwork associated with residual disease. Collectively, this study shows that current periodontal treatment results in partial restoration of a healthy microbial ecosystem, but features of biofilm dysbiosis and host inflammation remain in some patients, which were surprisingly independent of clinical response.

Oral Dysbiosis in Severe Forms of Periodontitis Is Associated With Gut Dysbiosis and Correlated With Salivary Inflammatory Mediators: A Preliminary Study

“…The present analyses indicated that the subgingival microbiome correlated with the salivary levels of certain mediators in patients with periodontitis ( Figure 4 ) and in healthy subjects ( Supplementary Figure 4 ), an observation that should contribute to the understanding of the role of specific members of the microbial community and the disease. We have chosen to correlate the inflammatory mediator levels in saliva with microbiome data of a pool of subgingival sites, as recently performed [ 73 ] but differing from other studies [ 28 , 74 ].…”

“…These data suggest that R. aeria and H. parainfluenzae are beneficial to the host. On the other hand, a longitudinal study on periodontitis subjects submitted to periodontal treatment reported that the abundance of Rothia showed negative associations with Selenomonas, Fusobacterium , and Prevotella [ 73 ]. Thus, it is possible that Rothia and/or H. parainfluenzae did not directly trigger CCL2 production or inhibit the production of inflammatory mediators but would meet suitable conditions for growth under an environment where inflammation is resolved.…”

Nonsurgical Periodontal Treatment Options and Their Impact on Subgingival Microbiota

“…One theory is that microbial diversity is higher in the subgingival plaque of patients with periodontitis [ 37 , 38 ], which is attributed to the greater pocket depth affecting the availability of nutrients and/or the impairment of the immune system, allowing the growth of a more diverse microbial community. In line with this theory, Johnston et al detected a decrease in alpha diversity after nonsurgical periodontal treatment [ 20 ].…”

“…They identified a reduction in bacteria of the orange and red complexes and an increase in Actinomyces species after periodontal therapy. In initial studies applying a comprehensive approach, next-generation sequencing (NGS) was used to investigate complex subgingival microbial changes due to nonsurgical periodontal therapy but without comparing different therapies [ 19 , 20 , 21 ].…”

A Single Dose of Nitrate Increases Resilience Against Acidification Derived From Sugar Fermentation by the Oral Microbiome

“…The salivary microbiota composition of six individuals was determined before and 4 h after nitrate intake. For analysis of the bacterial composition, R programming language (R Core Team, 2014) was used as described by Johnston et al (2021). In short, Wilcoxon sign rank (wilcox.test function) and Spearman's rho (cor.test function) tests were performed.…”