Probiotics with or without vitamin B12 added to non-surgical treatment for advanced periodontitis

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

This study will see if taking a probiotic lozenge alone or together with vitamin B12 during non-surgical periodontal treatment changes the oral microbiome and helps adults with Stage III or IV periodontitis.

Quick facts

• Phase: Not applicable
• Study type: Interventional
• Enrollment: 60 (estimated)
• Ages: 18 Years and up
• Sex: All
• Sponsor: University Hospital Heidelberg (Academic / other)
• Locations: 1 site (Heidelberg, Baden-Wurttemberg)
• Trial ID: NCT07443410 on ClinicalTrials.gov

What this trial studies

PROPARO is a single-center, randomized, controlled pilot trial enrolling adults with Stage III or IV periodontitis to compare guideline-concordant non-surgical periodontal therapy (NSPT) alone versus NSPT with a Limosilactobacillus reuteri lozenge or NSPT plus the lozenge and vitamin B12 drops. Participants are randomized 1:1:1 and receive standard mechanical debridement and supportive periodontal therapy while supplementing according to their assigned arm. The study collects supragingival and subgingival samples to characterize microbiome composition and tracks clinical periodontal measures over the treatment period. The goal is to determine community-level microbial changes and whether adjunctive supplements produce measurable differences compared with standard care.

Who should consider this trial

Good fit: Adults aged 18 or older with Stage III or IV periodontitis who can provide informed consent and attend treatment visits at the study center are the intended participants.

Not a fit: People who are pregnant or breastfeeding, recently used antibiotics or oral pre/probiotics, have uncontrolled systemic conditions that affect healing, or require systemic antibiotics for periodontal care are unlikely to benefit from this approach.

Why it matters

Potential benefit: If successful, adding these supplements could help rebalance the oral microbiome and support better healing after non-surgical periodontal treatment.

How similar studies have performed: Prior studies of Limosilactobacillus reuteri in periodontal care have reported mixed but sometimes positive clinical effects, while combined probiotic plus prebiotic approaches remain less well studied.

Eligibility criteria

Inclusion Criteria:

* Age ≥ 18 years

  * Stage III or IV periodontitis (localized or generalized)
  * Ability to provide informed consent
  * Written informed consent including data protection consent

Exclusion Criteria:

* • 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 this trial is running

Heidelberg, Baden-Wurttemberg

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

Study contacts

• Study coordinator: Diana Wolff, Prof. Dr.

Conditions Periodontitis, Adult; Periodontitis; Periodontitis Stage IV; Non-surgical periodontal treatment; Probiotics; Prebiotics; Oral Microbiome