Microbiological and Clinical Effects of Pre- and Probiotics in Non-Surgical Periodontal Therapy

Recruiting now · Not applicable · Has a placebo group

Conditions studied: Periodontitis, Adult, Periodontitis (Stage 3), Periodontitis Stage IV

In brief

Periodontitis is a prevalent chronic inflammatory disease driven by a dysbiotic oral biofilm and a dysregulated host immune response. Standard non-surgical periodontal therapy (NSPT) is primarily mechanical and, in selected cases, may be accompanied by antiseptics or systemic antibiotics. Targeted modulation of the oral microbiome ("microbiome engineering") is currently not part of routine periodontal care due to limited high-quality evidence. PROPARO is a single-center, randomized, controlled pilot study designed to assess whether adjunctive oral supplementation with a probiotic containing Limosilactobacillus reuteri (commercial dietary supplement lozenge) alone or combined with vitamin B12 (commercial dietary supplement drops) is associated with changes in supragingival and subgingival oral microbiome composition during guideline-concordant NSPT compared with standard care alone. Participants with Stage III or IV periodontitis will be randomized 1:1:1 to: (1) NSPT/SPT without supplementation (control), (2) NSPT/SPT plus probiotic lozenges for 3 months, or (3) NSPT/SPT plus probiotic lozenges and vitamin B12 drops for 3 months. The primary outcome is change in oral microbiome composition and structure (supragingival and subgingival), assessed using 16S rDNA-based profiling and metagenomic sequencing approaches. Secondary outcomes include clinical periodontal parameters (e.g., probing depth, clinical attachment level, bleeding on probing), oral hygiene/gingival indices, dental status, and participant-level ecological covariates (diet quality, perceived stress, physical activity). Sampling and assessments are aligned with routine care time points from baseline through supportive periodontal therapy follow-up (up to 12 months). This pilot trial aims to generate feasibility and effect-size estimates to inform future confirmatory studies and potential translation into guideline-based periodontal care.

Key facts

Study ID

NCT07443410

Run by

University Hospital Heidelberg

People needed

60

Starts

2024-10-25

Expected to finish

2026-10-01

Last updated by the study team

2026-03-02

Who can join

Age: 18 and older. Sex: any. Healthy volunteers: accepted.

You may qualify if…

• Age ≥ 18 years
• Stage III or IV periodontitis (localized or generalized)
• Ability to provide informed consent
• Written informed consent including data protection consent

You may not qualify if…

• • Pregnancy or breastfeeding
• Conditions/medications likely to substantially confound the oral microbiome or periodontal healing (e.g., uncontrolled diabetes mellitus, systemic immunosuppression, chronic steroid use)
• Antibiotic use within the last 3 months
• Use of oral pre-/probiotic supplements within the last 3 months
• Recent subgingival instrumentation within the last 6 months
• Need for obligatory adjunctive systemic antibiotic prophylaxis/therapy for NSPT
• Severe active systemic infection or other conditions judged by investigators to pose undue risk
• Regular use of antiseptic mouthrinses during the study period (unless medically required)
• Strict diets likely to substantially alter baseline microbiome trajectories (e.g., ketogenic, strict vegan) per protocol definition
• Chronic bowel diseases (for systemic confounding considerations)

Where it is running

• Heidelberg University Hospital — Heidelberg, Baden-Wurttemberg, Germany (enrolling)

Full record on ClinicalTrials.gov

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