Probiotic Response in Periodontal Disease (MicroPerio)

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

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.

Study Overview

• Status: Not yet recruiting
• Conditions: Periodontal Disease
• Intervention / Treatment: Dietary supplement: Placebo Lozenge; Dietary supplement: Probiotic Blend Lozenge

• Study Type: Interventional
• Enrollment (Estimated): 100
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Maria C Dao, PhD; Phone Number: (603) 862-4723; Email: carlota.dao@unh.edu
• Study Contact Backup: Name: Francesca Schembri, MS; Email: Francesca.Schembri@unh.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. 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.
2. 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:

1. 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.
2. 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.
3. 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.
4. 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.
5. Pregnancy or breastfeeding: Physiological changes during pregnancy and lactation may influence periodontal status, immune function, and microbiome composition.
6. Having fewer than 20 natural teeth: Adequate natural dentition is required to support standardized periodontal assessments and reliable biospecimen collection.
7. Use of removable dentures: Denture use alters the oral microbiome and local inflammatory environment and may compromise the validity of periodontal outcome measures.
8. 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.
9. Ongoing participation in another clinical trial: Concurrent participation in another trial may introduce overlapping interventions or behavioral changes that could compromise internal validity.
10. Lack of mobility or physical independence: Physical limitations may make participation burdensome or interfere with attendance at study visits and completion of study procedures.
11. 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.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Quadruple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Placebo Comparator: Placebo; Placebo lozenge (Ingredients: Isomalt, xylitol, peppermint flavor, menthol flavor and calcium sterate)	Dietary supplement: Placebo Lozenge; Daily placebo lozenge.
Experimental: Probiotic; Probiotic lozenge (Ingredients: Limosilactobacillus reuteri, isomalt, xylitol, peppermint flavor, menthol flavor and calcium sterate)	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.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Matrix metalloproteinase-8 (MMP-8)in gingival crevicular fluid (GCF)	MMP-8 is a validated biomarker of periodontal collagen breakdown	Change from baseline to week 12

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
C-reactive protein (CRP) in saliva and plasma	CRP is an acute phase protein used as marker of oral and systemic inflammation	Change from baseline to week 12
Interleukin 1β (IL-1β) in saliva and plasma	Interleukin IL-1β is a pro-inflammatory cytokine measured in saliva and plasma as an indicator of systemic and oral inflammatory response.	Change from baseline to week 12
IL-6 in saliva and plasma	Il-6 is a pro-inflammatory cytokine measured in saliva and plasma as an indicator of systemic and oral inflammatory response.	Change from baseline to week 12
IL-8 in saliva and plasma	IL-8 is a chemokine involved in neutrophil recruitment and local inflammatory activity, measured as a marker of periodontal inflammatory response.	Change from baseline to week 12
Tumor necrosis factor-alpha (TNF-α) in saliva and plasma	TNF-α is a pro-inflammatory cytokine associated with tissue inflammation and periodontal disease activity, measured to assess inflammatory modulation following probiotic supplementation.	Change from baseline to week 12
Oral microbiome composition	Relative abundance and diversity of bacterial taxa in oral samples, assessed to determine whether probiotic supplementation alters the microbial community associated with periodontal disease.	Change from baseline to week 12
Gut microbiome composition	Relative abundance and diversity of bacterial taxa in stool samples, assessed to evaluate whether probiotic supplementation affects gut microbial ecology.	Change from baseline to week 12
Oral and gut microbiome functional potential	Predicted or measured microbial gene pathway profiles, assessed to identify functional microbial features associated with inflammatory response and probiotic responsiveness.	Change from baseline to week 12

Collaborators and Investigators

• Sponsor: University of New Hampshire

Study record dates

Study Major Dates

• Study Start (Estimated): October 1, 2026
• Primary Completion (Estimated): November 1, 2027
• Study Completion (Estimated): July 1, 2028

Study Registration Dates

• First Submitted: July 16, 2026
• First Submitted That Met QC Criteria: July 16, 2026
• First Posted (Actual): July 21, 2026

Study Record Updates

• Last Update Posted (Actual): July 21, 2026
• Last Update Submitted That Met QC Criteria: July 16, 2026
• Last Verified: July 1, 2026

More Information

Terms related to this study

• Keywords: Microbiome; Probiotic; Periodontal disease
• Additional Relevant MeSH Terms: Mouth Diseases; Stomatognathic Diseases; Periodontal Diseases
• Other Study ID Numbers: UNH-17-FY2026_181-01

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

IPD Plan Description

All results will be reported in aggregate form using summary statistics. No direct identifiers will be included in publications, presentations, or shared datasets. Analytic files will contain only coded data linked to unique study IDs.

Because the study will enroll participants within a defined age range and geographic region, demographic variables will be reported in grouped categories, and small cell sizes will be aggregated or not report to prevent potential re-identification.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No