An observational study in Periodontitis and Type 2 Diabetes Mellitus (DM), sponsored by Akdeniz University. Active, not recruiting at 1 site in Turkey (Türkiye). Open to participants aged 18 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-10-29.
Sponsored by Akdeniz University · Observational
Periodontitis is a chronic inflammatory disease that affects the tissues supporting the teeth and can lead to progressive tissue destruction. Type 2 diabetes mellitus is a metabolic disease characterized by persistently elevated blood glucose levels. These two conditions are closely related, and genetic factors may influence their development and severity.
This observational study aims to evaluate the distribution of methylenetetrahydrofolate reductase (MTHFR) and DNA methyltransferase 3B (DNMT3B) gene polymorphisms in healthy individuals, individuals with periodontitis, individuals with type 2 diabetes mellitus, and individuals with both conditions. The study also aims to investigate the associations between these genetic variations and periodontal clinical parameters.
The study includes 200 participants divided into four groups of 50 individuals each: healthy individuals, individuals with type 2 diabetes without periodontitis, individuals with periodontitis without type 2 diabetes, and individuals with both type 2 diabetes and periodontitis.
Periodontal examinations include the assessment of plaque index, gingival index, probing pocket depth, clinical attachment loss, and gingival recession. Venous blood samples are collected for molecular analysis of MTHFR and DNMT3B gene polymorphisms.
The findings may contribute to a better understanding of the potential role of genetic factors in periodontal disease and its relationship with type 2 diabetes mellitus.
Periodontitis is a multifactorial chronic inflammatory disease characterized by inflammation and progressive destruction of the tooth-supporting tissues. Although microbial dental plaque is the primary etiological factor, the host immune response, environmental factors, and genetic susceptibility play important roles in the initiation and progression of the disease. Variations in disease severity among individuals highlight the potential contribution of genetic factors to periodontal disease pathogenesis.
Diabetes mellitus is a metabolic disease characterized by chronic hyperglycemia. It can impair immune system functions, enhance inflammatory responses, and accelerate periodontal tissue destruction. A bidirectional relationship between periodontitis and diabetes mellitus has been established. While diabetes increases the prevalence and severity of periodontal disease, periodontitis may negatively affect glycemic control by contributing to systemic inflammation. Therefore, both diseases may influence each other through shared pathophysiological mechanisms.
In recent years, increasing attention has been given to the role of genetic and epigenetic mechanisms in the pathogenesis of these diseases. The methylenetetrahydrofolate reductase (MTHFR) gene encodes an enzyme involved in folate metabolism and plays a critical role in the regulation of homocysteine metabolism. Commonly investigated MTHFR polymorphisms, including C677T (rs1801133) and A1298C (rs1801131), may reduce enzyme activity and contribute to elevated homocysteine levels, which have been associated with inflammation, oxidative stress, and vascular dysfunction.
The DNA methyltransferase 3B (DNMT3B) gene encodes an important epigenetic regulator involved in the regulation of gene expression through DNA methylation. The -149 C>T (rs2424913) polymorphism, located in the promoter region of the DNMT3B gene, may influence gene expression and modulate inflammatory responses. Through these mechanisms, this genetic variation may contribute to the pathogenesis of periodontal disease and diabetes mellitus.
Based on these findings, MTHFR and DNMT3B gene polymorphisms may play a role in the development and progression of periodontitis and diabetes mellitus. However, studies evaluating these genetic variations together with periodontal clinical parameters remain limited.
The primary aim of this study is to investigate the distribution of MTHFR and DNMT3B gene polymorphisms among healthy individuals, individuals with periodontitis alone, individuals with type 2 diabetes mellitus alone, and individuals with both type 2 diabetes mellitus and periodontitis. Additionally, the study aims to evaluate the associations between these genetic variations and periodontal clinical parameters, including plaque index, gingival index, probing pocket depth, clinical attachment loss, and gingival recession.
This observational study is conducted at the Department of Periodontology, Faculty of Dentistry, Akdeniz University, Antalya, Türkiye. A total of 200 participants are included in four groups, each consisting of 50 individuals:
All participants undergo a comprehensive periodontal clinical examination. Periodontal parameters include the plaque index to assess dental plaque accumulation, gingival index to evaluate gingival inflammation, probing pocket depth to determine the depth of periodontal pockets, clinical attachment loss to assess periodontal tissue destruction, and gingival recession to determine the extent of gingival tissue recession.
Venous blood samples are collected from participants, and molecular methods are used to analyze MTHFR and DNMT3B gene polymorphisms. The collected clinical and genetic data will be statistically evaluated to investigate the associations between genetic polymorphisms and periodontal clinical parameters across the four study groups.
The results of this study may provide further insight into the potential contribution of genetic and epigenetic factors to periodontal disease and the relationship between periodontitis and type 2 diabetes mellitus.
1,231 studies on the registry are indexed under Periodontitis; 295 are open to participants now.
This study's enrollment of 200 is above the median of 90 across 372 observational studies indexed under Periodontitis.
Browse Periodontitis studies →Akdeniz University is the lead sponsor of 297 studies on the registry; 62 are open to participants now.
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The study population consists of 200 adults recruited from the Department of Periodontology, Faculty of Dentistry, Akdeniz University, Antalya, Türkiye. Participants are divided into four groups of 50 individuals each: systemically and periodontally healthy controls, individuals with type 2 diabetes mellitus without periodontitis, individuals with periodontitis without type 2 diabetes mellitus, and individuals with both type 2 diabetes mellitus and periodontitis. Periodontal clinical parameters are recorded, and venous blood samples are collected for the analysis of MTHFR and DNMT3B gene polymorphisms.
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 group consists of 50 systemically and periodontally healthy individuals without type 2 diabetes mellitus or periodontitis. Periodontal clinical parameters are evaluated, and venous blood samples are collected for the analysis of MTHFR and DNMT3B gene polymorphisms.
Diagnostic Test: MTHFR and DNMT3B Genetic Polymorphism Analysis
This group consists of 50 individuals diagnosed with type 2 diabetes mellitus without periodontitis. Periodontal clinical parameters are evaluated, and venous blood samples are collected for the analysis of MTHFR and DNMT3B gene polymorphisms.
Diagnostic Test: MTHFR and DNMT3B Genetic Polymorphism Analysis
This group consists of 50 individuals diagnosed with periodontitis without type 2 diabetes mellitus. Periodontal clinical parameters are evaluated, and venous blood samples are collected for the analysis of MTHFR and DNMT3B gene polymorphisms.
Diagnostic Test: MTHFR and DNMT3B Genetic Polymorphism Analysis
This group consists of 50 individuals diagnosed with both type 2 diabetes mellitus and periodontitis. Periodontal clinical parameters are evaluated, and venous blood samples are collected for the analysis of MTHFR and DNMT3B gene polymorphisms.
Diagnostic Test: MTHFR and DNMT3B Genetic Polymorphism Analysis
Venous blood samples are collected from participants in all four study groups. DNA extracted from these samples is analyzed to identify MTHFR (C677T and A1298C) and DNMT3B (-149 C\>T) gene polymorphisms. The genetic findings will be evaluated in relation to periodontal clinical parameters and the presence of type 2 diabetes mellitus and periodontitis. No therapeutic intervention is administered as part of this observational study.
MTHFR C677T (rs1801133) Genotype Distribution
The distribution of MTHFR C677T (rs1801133) genotypes (CC, CT, and TT) will be determined using DNA extracted from venous blood samples. Genotype frequencies will be compared among the four study groups: healthy individuals, individuals with type 2 diabetes mellitus only, individuals with periodontitis only, and individuals with both conditions.
Time frame: At baseline (single blood sample collection)
MTHFR A1298C (rs1801131) Genotype Distribution
The distribution of MTHFR A1298C (rs1801131) genotypes (AA, AC, and CC) will be determined using DNA extracted from venous blood samples. Genotype frequencies will be compared among four study groups: healthy individuals, individuals with type 2 diabetes mellitus only, individuals with periodontitis only, and individuals with both type 2 diabetes mellitus and periodontitis.
Time frame: At baseline (single blood sample collection)
DNMT3B -149C>T (rs2424913) Genotype Distribution
The distribution of DNMT3B -149C\>T (rs2424913) genotypes (CC, CT, and TT) will be determined using DNA extracted from venous blood samples. Genotype frequencies will be compared among four study groups: healthy individuals, individuals with type 2 diabetes mellitus only, individuals with periodontitis only, and individuals with both type 2 diabetes mellitus and periodontitis.
Time frame: At baseline (single blood sample collection)
Plaque Index (PI) Score
Plaque accumulation will be assessed using the Plaque Index (PI). The PI score will be recorded during the baseline periodontal examination and compared among four study groups: healthy individuals, individuals with type 2 diabetes mellitus only, individuals with periodontitis only, and individuals with both type 2 diabetes mellitus and periodontitis.
Time frame: At baseline (single periodontal examination)
Gingival Index (GI) Score
Gingival inflammation will be assessed using the Gingival Index (GI). The GI score will be recorded during the baseline periodontal examination and compared among four study groups: healthy individuals, individuals with type 2 diabetes mellitus only, individuals with periodontitis only, and individuals with both type 2 diabetes mellitus and periodontitis.
Time frame: At baseline (single periodontal examination)
Probing Pocket Depth (PPD)
Probing Pocket Depth (PPD) will be measured in millimeters (mm) using a periodontal probe during the baseline periodontal examination. PPD values will be compared among four study groups: healthy individuals, individuals with type 2 diabetes mellitus only, individuals with periodontitis only, and individuals with both type 2 diabetes mellitus and periodontitis.
Time frame: At baseline (single periodontal examination)
Clinical Attachment Loss (CAL)
Clinical Attachment Loss (CAL) will be measured in millimeters (mm) as the distance from the cementoenamel junction to the base of the periodontal pocket using a periodontal probe. CAL values will be recorded during the baseline periodontal examination and compared among four study groups: healthy individuals, individuals with type 2 diabetes mellitus only, individuals with periodontitis only, and individuals with both type 2 diabetes mellitus and periodontitis.
Time frame: At baseline (single periodontal examination)
Gingival Recession (GR)
Gingival Recession (GR) will be measured in millimeters (mm) as the distance from the cementoenamel junction to the gingival margin using a periodontal probe. GR values will be recorded during the baseline periodontal examination and compared among four study groups: healthy individuals, individuals with type 2 diabetes mellitus only, individuals with periodontitis only, and individuals with both type 2 diabetes mellitus and periodontitis.
Time frame: At baseline (single periodontal examination)
Plan to share: No — Individual participant data (IPD) will not be shared with other researchers due to participant confidentiality and the sensitive nature of genetic and clinical health information. The collected data will be used exclusively for the purposes of the approved research study. Study findings will be reported in aggregate form without disclosing individual participant information.
Ran from Apr 2026 to primary completion in Aug 2026, 4 months.
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