An observational study in Periodontitis (Stage 3), Periodontitis Stage IV and SIBO, sponsored by Iuliu Hatieganu University of Medicine and Pharmacy. Recruiting at 1 site in Romania. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-11-04.
Sponsored by Iuliu Hatieganu University of Medicine and Pharmacy · Observational
Periodontitis is a chronic inflammatory disease characterized by dysbiotic subgingival biofilms, inflammation, and progressive destruction of the tooth-supporting tissues. Beyond the local periodontal lesion, periodontal inflammation may contribute to systemic inflammatory burden through the dissemination of microbial products and inflammatory mediators.
The oral cavity and intestinal tract are closely connected through continuous microbial exposure, swallowing of oral microorganisms, host immune pathways, and systemic circulation. Emerging evidence suggests that periodontal inflammation may be associated with alterations of the intestinal microbial environment and gut barrier function. However, the human evidence remains heterogeneous and does not currently establish a causal relationship between periodontitis and intestinal dysbiosis or small intestinal bacterial overgrowth (SIBO).
SIBO represents an abnormal increase and/or alteration of bacterial populations in the small intestine and may be associated with gastrointestinal symptoms and intestinal microbial imbalance. The occurrence of SIBO in patients with advanced periodontitis has not been adequately characterized. Consequently, determining how frequently SIBO is detected in a clinically well-characterized cohort of participants with Stage III periodontitis may provide useful exploratory data and may support future controlled studies.
Alterations in the intestinal microbial environment may be accompanied by changes in intestinal barrier function and increased systemic exposure to bacterial products. Zonulin has been investigated as a biomarker related to intestinal barrier regulation, while lipopolysaccharide-binding protein (LBP) may provide information regarding systemic exposure to bacterial products. These biomarkers should be interpreted as indirect biological indicators rather than as direct measurements of intestinal permeability.
The present study therefore approaches the oral-gut-systemic interface from an exploratory clinical perspective. It does not aim to demonstrate that periodontitis causes SIBO. Instead, it seeks to characterize the occurrence of SIBO in participants with severe periodontitis and to explore whether SIBO is accompanied by alterations in intestinal barrier-related biomarkers and systemic exposure to bacterial products. The longitudinal component will further examine whether improvement in periodontal clinical status following routine, clinically indicated periodontal therapy is accompanied by changes in SIBO status and these biological markers.
Periodontitis is a chronic inflammatory disease associated with dysbiotic changes in the oral microbiome. Interactions between the oral and intestinal microbial environments may influence host inflammatory responses and intestinal barrier function. However, the clinical relationships between severe periodontitis, small intestinal bacterial overgrowth (SIBO), and circulating biomarkers related to intestinal barrier function and bacterial exposure remain insufficiently characterized.
This study will investigate these relationships in adults with Stage III/IV periodontitis, Grade B or C. The study will include 20 participants in a single prospective cohort, without a healthy control or comparison group. The study is exploratory and is intended to characterize clinical and biological associations rather than establish causal relationships.
The research will integrate standardized periodontal examination with hydrogen and methane breath testing using lactulose and/or glucose. Serum zonulin and lipopolysaccharide-binding protein (LBP) will be assessed as biomarkers related to intestinal barrier function and systemic exposure to bacterial products, respectively. Gastrointestinal symptoms and relevant clinical and lifestyle characteristics will also be considered when interpreting the findings.
A longitudinal component will examine whether changes in periodontal clinical status following routine, clinically indicated periodontal therapy are accompanied by changes in SIBO status and serum biomarker levels. Follow-up assessment is planned approximately 6-8 weeks after completion of etiological periodontal treatment.
The study is expected to provide preliminary clinical data on the potential relationships between periodontal disease, intestinal microbial alterations, and systemic inflammatory processes. The findings may help generate hypotheses for future larger controlled studies.
1,231 studies on the registry are indexed under Periodontitis; 295 are open to participants now.
This study's planned enrollment of 20 is below the median of 90 across 372 observational studies indexed under Periodontitis.
Browse Periodontitis studies →Iuliu Hatieganu University of Medicine and Pharmacy is the lead sponsor of 56 studies on the registry; 15 are open to participants now.
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Adults diagnosed with Stage III/IV periodontitis who meet the study's eligibility criteria will be recruited from the Outpatient Dental Clinic of the County Emergency Clinical Hospital (SCJU) Cluj-Napoca, Romania. Participants will undergo periodontal clinical assessment, testing for small intestinal bacterial overgrowth (SIBO), and blood sampling for the assessment of selected serum biomarkers. Eligible participants will receive non-surgical periodontal therapy as specified in the study protocol.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
This study includes a single group of patients with Stage III/IV periodontitis. Participants will undergo a comprehensive periodontal examination, assessment for small intestinal bacterial overgrowth (SIBO) using hydrogen and methane breath testing, and blood sampling for the assessment of serum biomarkers related to intestinal barrier function and systemic inflammation, including zonulin and lipopolysaccharide (LPS). Gastrointestinal symptoms will also be assessed using a questionnaire. Participants will receive standard non-surgical periodontal therapy, including scaling and root planing, according to clinical indications. Periodontal clinical parameters and selected serum biomarkers will be reassessed 6-8 weeks after treatment. No control group is included.
Small Intestinal Bacterial Overgrowth (SIBO) Prevalence Assessed by Hydrogen and Methane Breath Testing
The presence of small intestinal bacterial overgrowth (SIBO) will be assessed using a hydrogen and methane breath test following administration of the specified test substrate. Breath samples will be collected at predefined intervals and analyzed for hydrogen and methane concentrations. SIBO status will be classified as positive or negative according to the prespecified diagnostic criteria. Prevalence will be calculated as the percentage of participants with a positive test result among all participants evaluated at baseline.
Time frame: At baseline, before periodontal treatment.
Serum Zonulin Concentration Measured by Enzyme-Linked Immunosorbent Assay
Serum zonulin concentrations will be determined using an enzyme-linked immunosorbent assay (ELISA). Blood samples will be collected and processed to obtain serum for quantitative determination of zonulin. Measurements will be performed at baseline, before periodontal treatment, and at follow-up, 6-8 weeks after completion of periodontal treatment. Changes in serum zonulin concentrations between the two time points will be evaluated and analyzed in relation to SIBO status and periodontal clinical parameters.
Time frame: At baseline, before periodontal treatment, and 6-8 weeks after completion of periodontal treatment.
Serum Lipopolysaccharide-Binding Protein Concentration Measured by Enzyme-Linked Immunosorbent Assay
Serum lipopolysaccharide-binding protein (LBP) concentrations will be determined using an enzyme-linked immunosorbent assay (ELISA). Blood samples will be collected and processed to obtain serum for quantitative determination of LBP. Measurements will be performed at baseline, before periodontal treatment, and at follow-up, 6-8 weeks after completion of periodontal treatment. Changes in serum LBP concentrations between the two time points will be evaluated and analyzed in relation to SIBO status and periodontal clinical parameters.
Time frame: At baseline, before periodontal treatment, and 6-8 weeks after completion of periodontal treatment.
Periodontal Probing Pocket Depth Measured by Periodontal Probing
Periodontal probing pocket depth (PPD) will be assessed using a periodontal probe at the examined tooth sites. PPD is defined as the distance, in millimeters, from the gingival margin to the bottom of the periodontal pocket. Measurements will be recorded for each examined site, and the mean PPD per participant will be calculated for analysis.
Time frame: At baseline, before periodontal treatment, and 6-8 weeks after completion of periodontal treatment.
Clinical Attachment Level Measured by Periodontal Probing
Clinical attachment level (CAL) will be assessed using a periodontal probe at the examined tooth sites. CAL is defined as the distance, in millimeters, from the cemento-enamel junction to the bottom of the periodontal pocket. Measurements will be recorded for each examined site, and the mean CAL per participant will be calculated for analysis.
Time frame: At baseline, before periodontal treatment, and 6-8 weeks after completion of periodontal treatment.
Bleeding on Probing Percentage Assessed During Periodontal Examination
Bleeding on probing (BOP) will be assessed following periodontal probing at the examined tooth sites. The presence or absence of bleeding will be recorded for each site. The BOP percentage will be calculated as the number of sites presenting bleeding divided by the total number of examined sites, multiplied by 100.
Time frame: At baseline, before periodontal treatment, and 6-8 weeks after completion of periodontal treatment.
Body Mass Index (BMI) Calculated from Weight and Height Measurements
Body mass index (BMI) will be calculated for each participant by dividing body weight in kilograms by the square of height in meters (kg/m²). Weight and height will be measured using standard anthropometric procedures. BMI values will be recorded at baseline and analyzed as potential clinical confounders in relation to SIBO status and periodontal clinical parameters.
Time frame: At baseline, before periodontal treatment.
Gastrointestinal Symptom Severity Assessed Using the Gastrointestinal Symptom Rating Scale (GSRS)
Gastrointestinal symptoms will be assessed at baseline using the Gastrointestinal Symptom Rating Scale (GSRS), a standardized questionnaire evaluating the severity of gastrointestinal symptoms across different domains. Participants will complete the questionnaire, and the total GSRS score will be calculated according to the instrument's scoring instructions. The total score will be used to characterize gastrointestinal symptom burden and explore its relationship with SIBO status and periodontal clinical parameters.
Time frame: At baseline, before periodontal treatment.
Gastrointestinal Symptom Severity Assessed Using the Visual Analog Scale for Irritable Bowel Syndrome (VAS-IBS)
Gastrointestinal symptoms will be assessed at baseline using the Romanian version of the VAS-IBS questionnaire (ROME IV). The questionnaire evaluates abdominal pain frequency, gastrointestinal symptom severity (including abdominal pain, diarrhea, constipation, bloating and gas, and nausea and vomiting), stool consistency, emotional well-being, the impact of gastrointestinal symptoms on daily life, and bowel-related symptoms. Responses will be recorded and analyzed according to the individual scoring scales and response categories specified in the questionnaire. The results will be used to characterize gastrointestinal symptom burden and explore its relationship with SIBO status and periodontal clinical parameters.
Time frame: At baseline, before periodontal treatment.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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Iuliu Hatieganu University of Medicine and Pharmacy