Probiotic Response in Periodontal Disease

Official title

MicroPerio: Microbiome and Dietary Predictors of Probiotic Response in Periodontal Disease

Overview

Probiotics are live microorganisms that can be taken as supplements and have shown promise in playing a beneficial role in improving clinical conditions that are characterized by chronic inflammation, such as periodontal disease (PD). The human gut microbiome is composed of trillions of bacteria that reside throughout the gastrointestinal tract and has an important role in the modulation of inflammatory responses in the human host. There is evidence that PD is associated with alterations in the oral and gut microbiomes, suggesting that probiotics may reduce inflammation through microbiome modulation. However, individual responses to probiotics can be highly variable, and robust predictors of probiotic responsiveness remain poorly defined. There is also limited knowledge about how the oral and gut microbiome interact even though there is growing evidence for a bidirectional oral-gut axis with implications for host immunity, inflammation, and probiotic responsiveness. The overarching goal of this project is to identify oral and gut microbiome features that predict responsiveness to probiotic interventions as an adjuvant treatment for PD. We will conduct a double-blind randomized controlled trial in which New Hampshire adults with stage III PD will be randomized to receive a 12-week adjuvant intervention of either a daily probiotic (n=45) or placebo (n=45) lozenge. The probiotic intervention will consist of a once daily lozenge containing a standard dose of 200 million CFU of two strains of Limosilactobacillus reuteri (DSM 17938 and ATCC PTA 5289), a commercial formulation demonstrated to be safe and well-tolerated in this population over this treatment length. The primary outcome to quantify responsiveness to the probiotic as an adjuvant therapeutic for PD will be within-subject change from baseline in inflammatory markers, and oral and gut microbiome composition.

Interventions

• Dietary supplement Probiotic Blend Lozenge
  L. reuteri is a probiotic that has been shown to inhibit the activity of "red complex" species and reduce PD severity in vitro and in animal models, and has been shown to ameliorate clinical outcomes of PD in human trials.
• Dietary supplement Placebo Lozenge
  Daily placebo lozenge.

Primary outcome measures

• Matrix metalloproteinase-8 (MMP-8)in gingival crevicular fluid (GCF) [Time frame: Change from baseline to week 12]

Secondary outcome measures (8)

• C-reactive protein (CRP) in saliva and plasma [Time frame: Change from baseline to week 12]
• Interleukin 1β (IL-1β) in saliva and plasma [Time frame: Change from baseline to week 12]
• IL-6 in saliva and plasma [Time frame: Change from baseline to week 12]
• IL-8 in saliva and plasma [Time frame: Change from baseline to week 12]
• Tumor necrosis factor-alpha (TNF-α) in saliva and plasma [Time frame: Change from baseline to week 12]
• Oral microbiome composition [Time frame: Change from baseline to week 12]
• Gut microbiome composition [Time frame: Change from baseline to week 12]
• Oral and gut microbiome functional potential [Time frame: Change from baseline to week 12]

Eligibility criteria

Inclusion criteria

• Age between 45 and 65 years: Restricting eligibility to this age range reduces potential confounding from age-related comorbidities and ensures adequate natural dentition for standardized gingival crevicular fluid (GCF) sampling.
• Diagnosis of Stage III periodontal disease (PD): Participants must have clinically confirmed Stage III (severe) PD according to the 2017 American Academy of Periodontology/European Federation of Periodontology (AAP/EFP) classification system to ensure consistent disease severity among enrolled participants.

Exclusion criteria

• Use of prebiotic, probiotic, or fiber supplements within the previous 6 months: Recent use of microbiome-modulating supplements could alter baseline oral or gut microbial composition and confound assessment of responsiveness to the probiotic intervention.
• Use of antibiotics within the previous 6 months: Antibiotic exposure can cause sustained disruptions to host microbiomes and immune responses, which may confound evaluation of probiotic-related changes in inflammatory and microbial outcomes.
• Systemic diseases affecting the periodontium (uncontrolled diabetes mellitus defined as HbA1c ≥8%, autoimmune diseases): These conditions may independently influence periodontal inflammation, immune responses, and microbiome composition, potentially confounding interpretation of study outcomes.
• History of communicable or chronic diseases that may render study participation unsafe: Certain medical conditions may increase the risk of adverse events associated with study procedures or probiotic exposure.
• Pregnancy or breastfeeding: Physiological changes during pregnancy and lactation may influence periodontal status, immune function, and microbiome composition.
• Having fewer than 20 natural teeth: Adequate natural dentition is required to support standardized periodontal assessments and reliable biospecimen collection.
• Use of removable dentures: Denture use alters the oral microbiome and local inflammatory environment and may compromise the validity of periodontal outcome measures.
• Surgical periodontal disease treatment within the previous 6 months: Recent surgical intervention may induce substantial changes in the periodontal environment, complicating baseline measurement and interpretation of treatment response.
• Ongoing participation in another clinical trial: Concurrent participation in another trial may introduce overlapping interventions or behavioral changes that could compromise internal validity.
• Lack of mobility or physical independence: Physical limitations may make participation burdensome or interfere with attendance at study visits and completion of study procedures.
• Inability to communicate orally or in written English: Because study procedures and consent materials will be conducted in English, adequate language proficiency is required to ensure participants understand study instructions and provide informed consent.

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Quadruple blind

Primary purpose

Treatment

Study locations

Center list to be confirmed — check the primary protocol.

Identifiers

NCT: NCT07718074 · UNH-17-FY2026_181-01

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗