An observational study in Periodontitis, Osteo Arthritis Knee and Hip and Bacteriaemia, sponsored by University of Zagreb. Recruiting at 2 sites in Croatia. Open to participants aged 18 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-11-13.
Sponsored by University of Zagreb · Observational
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The aim of the study is to determine the prevalence of periodontitis in patients with osteoarthritis. Methods: A case-control study is planned. The research would include patients of the Orthopaedic Clinic, University Hospital Centre Zagreb that have been diagnosed with osteoarthritis (cases). The control group would be patients from the Dental Polyclinic Zagreb, where the research will be conducted. All patients would undergo a dental examination to determine their periodontal status and periodontitis stage. Demographic parameters would include: age, gender, education, alcohol and cigarette consumption, exercise habits, BMI, oral hygiene habits, medication and medical history. Expected results: The aim of the study is to determine if there is a link between periodontitis and osteoarthritis. In patients with osteoarthritis a higher prevalence of periodontitis is expected, as well as more advanced stages of periodontitis, compared to the subjects of the control group. Scientific contribution: The results of the study might further confirm and strengthen the association between periodontitis and osteoarthritis. For the first time the proposed study will explore the presence of five key periodontopathogens in periodontal tissues and synovial fluid patients with periodontitis and osteoarthritis and examine the quality of life related to oral health.
1,235 studies on the registry are indexed under Periodontitis; 295 are open to participants now.
This study's planned enrollment of 60 is below the median of 90 across 372 observational studies indexed under Periodontitis.
Browse Periodontitis studies →University of Zagreb is the lead sponsor of 72 studies on the registry; 15 are open to participants now.
Counted across the registry records on this site, refreshed daily.
The research would include patients from the Orthopedic Clinic of the University Hospital Centre Zagreb who have been diagnosed with knee or hip osteoarthritis (study group), and patients from the Dental Polyclinic Zagreb (control group), where the research will also be conducted. Patients would be divided into two subgroups depending on whether they have periodontitis or not.
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.
Diagnosed primary osteoarthritis of grade 4 according to the Kellgren-Lawrence scale Patients who are independently mobile or mobile with the aid of a walker or forearm crutches Signed Minimum of twenty teeth in the jaw (third molars are excluded)
Exclusion Criteria:
Use of systemic antibiotics or periodontal therapy performed within the last six months Systemic diseases known to be risk factors for the development of periodontitis (diabetes mellitus, obesity, rheumatoid arthritis, depression, hematological diseases) Secondary osteoarthritis Parkinson's disease Pregnant or breastfeeding women Neoplasms
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.
Other: No Interventions
Other: No Interventions
This is an observational study, and participants did not receive any study-specific intervention measures.
PPD
Periodontal probing depth - the distance in millimeters from the gingival margin to the base of the periodontal pocket. It is measured using a standard periodontal probe at 6 sites per tooth. Higher values indicate deeper periodontal pockets (worse periodontal status), while lower values indicate shallower pockets (better periodontal status).
Time frame: Baseline (single assessment)
PCR microbiological testing
PCR test (polymerase chain reaction, 7500 Real-Time PCR System, Applied Biosystems/Method RT-PCR with Sybr-Green/melting curve analysis, validated according to micro-IDent®, Hain Lifescience GmbH, CE-IVD and PeriodontScreen Real-TM CE, Sacace Biotechnologies) is planned for the most common periodontopathogenic bacteria: Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythensis, Prevotella intermedia, and Treponema denticola. The test would be taken from all patients in the study group diagnosed with periodontitis. Samples of bacteria would be collected from the periodontal pocket and synovial fluid. When testing bacteria from periodontal pockets, sterile paper points are inserted to the bottom of the deepest pockets and left in situ for 20 seconds. The paper points are then placed in a sterile test tube, tightly closed, and sent to the molecular laboratory of the Analiza Polyclinic. The procedure for collecting bacteria from synovial fluid also include
Time frame: Baseline (single assessment)
OHIP-14
OHIP-14 is a 14-item questionnaire that assesses the impact of oral health on oral health-related quality of life. Each item is scored on a Likert scale from 0 to 4 (0 = never, 1 = hardly ever, 2 = occasionally, 3 = fairly often, 4 = very often). The total score ranges from 0 to 56. Higher scores indicate worse oral health-related quality of life, while lower scores indicate better oral health-related quality of life.
Time frame: Baseline (single assessment)
RE
Gingival recession is the distance in millimeters from the cementoenamel junction to the gingival margin. It is measured using a standard periodontal probe. Higher values indicate more pronounced gingival recession (worse condition), while lower values or a value of 0 indicate a normal position of the gingival margin.
Time frame: Baseline (single assessment)
CAL
Clinical attachment level is the sum of probing depth and gingival recession at a given tooth site, expressed in millimeters. It represents the distance from the cementoenamel junction to the base of the periodontal pocket. Higher values indicate greater clinical attachment loss (worse condition), while lower values indicate a more preserved periodontal supporting structures.
Time frame: Baseline (single assessment)
FMPS
Full-mouth plaque score - plaque accumulation will be assessing the presence or absence of supragingival plaque on six surfaces of each tooth. The results will be expressed as the percentage of plaque-positive surfaces relative to the total number of examined surfaces. FMPS is calculated by dividing the number of sites with plaque by the total number of examined sites and multiplying by 100. Scores range from 0% to 100%. Higher percentages indicate greater plaque accumulation (worse condition), while lower percentages indicate better oral hygiene.
Time frame: Baseline (single assessment)
FMBS
Full-mouth bleeding score - gingival inflammation will be assessed recorded dichotomously (presence/absence of bleeding) following gentle probing of the gingival sulcus at standardized sites. The outcome will be expressed as the percentage of bleeding-positive sites, reflecting the degree of gingival inflammatory response. FMBS is calculated by dividing the number of bleeding sites by the total number of examined sites and multiplying by 100. Scores range from 0% to 100%. Higher percentages indicate greater gingival inflammation (worse condition), while lower percentages indicate healthier gingival tissue.
Time frame: Baseline (single assessment)
Plan to share: No
No publications or documents are linked to this record.
Started Jan 2025 (actual). Primary completion is estimated for Jun 2027, 28 months after the start.
How these figures are worked out, and which studies are left out of them.
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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University of Zagreb