Microbiological Modulation Of The Oral-Gut Axis After Treatment With Or Without Systemic Use Of Probiotics In Patients With Periodontitis: A Randomized Controlled Clinical Study.

Periodontitis is a chronic inflammatory disease of multifactorial origin, characterizedby the destruction of the tooth‐supporting tissues as a result of the interaction betweena dysbiotic biofilm and the host immunoinflammatory response. Recent evidence suggeststhat the oral microbiota may influence the gut microbiota through the oral‐gut axis,contributing to local and systemic alterations. In this context, the use of probiotics asan adjunctive therapy to conventional periodontal treatment may favor the restoration ofmicrobial balance and reduce inflammation.The aim of this study is to evaluate the impact of systemic probiotic therapy, used as anadjunct to scaling and root planing (SRP), on the microbiological modulation of theoral‐gut axis in patients with periodontitis. In addition, the effects of theintervention on periodontal clinical parameters, the immunoinflammatory profile, and thecomposition of the oral and gut microbiota will be investigated.This randomized, placebo‐controlled clinical trial will include 40 systemically healthyparticipants aged 30 years or older, diagnosed with generalized Stage III or IV, GradeB/C periodontitis, recruited at the School of Dentistry of Ribeirão Preto, University ofSão Paulo (FORP/USP). Participants will be randomly allocated into two groups: one groupwill receive scaling and root planing associated with the probiotic Bifidobacteriumanimalis subsp. lactis HN019, whereas the other group will receive the same periodontaltreatment associated with placebo. The probiotic or placebo will be administered orallyat a dose of one capsule per day for 30 days.Periodontal clinical parameters will be recorded, including plaque index, bleeding index,probing depth, bleeding on probing, and clinical attachment level. The immunoinflammatoryprofile will be evaluated by quantifying CCL19, IL‐6, TNF‐α, IL‐1β, and IL‐17 in gingivalcrevicular fluid using multiplex assays (Luminex). To investigate modulation of theoral‐gut axis, subgingival biofilm and fecal samples will be collected before and afterthe intervention for analysis of the oral and gut microbiota.The results will allow us to determine whether the systemic administration ofBifidobacterium animalis subsp. lactis HN019 enhances the effects of non‐surgicalperiodontal therapy, promoting clinical, immunological, and microbiological improvementscompared with placebo.