Impact of systemic probiotics as adjuncts to subgingival instrumentation on the oral‐gut microbiota associated with periodontitis: A randomized controlled clinical trial

Background The oral‐gut axis may be a route linking periodontal and systemic diseases. Probiotics could be an alternative for the treatment of microbial dysbiotic conditions, including periodontitis. This randomized placebo‐controlled clinical trial evaluated the short‐term efficacy of systemic probiotics adjunctive to subgingival instrumentation (SI) in promoting a better restoration of the oral‐gut microbiotas and greater periodontal clinical outcome. Methods Systemically healthy adults with untreated periodontitis were recruited from a Dental School setting and allocated to receive SI plus placebo (n = 24) or probiotics (n = 24), one capsule/day for 30 days. Subgingival biofilm and stool were obtained at baseline and 2‐months post‐therapy for microbiological analyses by checkerboard and 16S rRNA gene sequencing. Differences in all parameters between placebo (n = 23) and probiotics (n = 19) groups were assessed by non‐parametric tests. Results Most subgingival species and α‐diversity decreased after therapies (P