Investigation of the Relationship Between Periodontitis and Alzheimer's Disease in Terms of Blood Parameters

Uskudar University100 enrolled

Overview

The aim of this study was to analyse the possible relationship between periodontal inflammation and Alzheimer's disease and to investigate the role of blood parameters in this relationship.

This retrospective case-control study will include individuals who were clinically and radiographically examined, diagnosed with periodontal disease, read and signed informed consent forms between March 2022 and July 2025 at the Periodontology Departments of Bezmialem Vakif University, Uskudar University and Bolu Abant Izzet Baysal University Faculty of Dentistry. In this study, two groups will be formed as a case group consisting of individuals with periodontitis diagnosed with probable Alzheimer's disease according to NINCDS-ADRDA and DSM-V diagnostic criteria and a control group consisting of individuals with periodontitis only. Patients who underwent periodontal evaluations at six sites per tooth, with the following parameters recorded-plaque percentage, probing pocket depth, percentage of bleeding on probing, clinical attachment level, number of teeth, and periodontal inflamed surface area (PISA)-will be included in the study. Compliance with the inclusion and exclusion criteria will be verified through patient files and digital records. In individuals with a probable diagnosis of Alzheimer's disease according to NINCDS-ADRDA and DSM-V diagnostic criteria, disease stage as determined by the Clinical Dementia Rating scale and Standardized Mini-Mental Test (SMMT) scores will also be recorded. Hematological data will be obtained from patients' recorded complete blood count test results and the following parameters will be utilized: * White blood cell count, neutrophil, lymphocyte, monocyte, eosinophil, basophil counts and percentages, neutrophil/lymphocyte ratio (NLR), monocyte/lymphocyte ratio (MLR) * Platelet count, platelet/lymphocyte ratio (PLR), platelet distribution width (PDW), mean platelet volume (MPV), plateletcrit (PCT) * Erythrocyte count, hemoglobin (HGB), hematocrit (HCT), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), red blood cell distribution width (RDW) * In addition, inflammation indicators such as pan-immune inflammation value (PIV), systemic immune-inflammation index (SII) and hemoglobin/erythrocyte ratio (HRR), which are formulated from the above parameters, will also be recorded.

Study Type

OBSERVATIONAL

Enrollment

100

Conditions

Periodontal Disease Periodontitis Periodontal Inflammation Biomarkers / Blood Blood Cell Count Alzheimer Disease

Interventions

Complete Blood Count TestDIAGNOSTIC_TEST

Complete blood count test provides data on total white blood cell count, neutrophil count, neutrophil percentage, lymphocyte count, lymphocyte percentage, monocyte count, monocyte percentage, eosinophil count, eosinophil percentage, basophil count, basophil percentage, platelet count, platelet distribution width (PDW), mean platelet volume (MPV), plateletcrit (PCT), erythrocyte count, hemoglobin, hematocrit (HCT), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC) and red blood cell distribution width (RDW). In addition, neutrophil-lymphocyte ratio (NLR), monocyte-lymphocyte ratio (MLR), platelet-leukocyte ratio (PLR), Pan-Immune-Inflammation Value (PIV), Systemic Immune-Inflammation Index (SII), Hemoglobin-to-Red Cell Distribution Width Ratio (HRR) values are also formulated from these parameters.

Periodontal examinationsDIAGNOSTIC_TEST

With periodontal evaluation, plaque percentage, probing pocket depth, percentage of bleeding on probing, clinical attachment level, number of teeth, periodontal inflammatory surface area (PISA) parameters are recorded.

Eligibility

Sex: ALLMin age: 50 YearsMax age: 90 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Between March 2022 and July 2025, those who applied to the Periodontics Departments of the Dentistry Faculties of Uskudar University, Bezmialem Vakif University and Bolu Abant Izzet Baysal University, * Informed consent form was obtained during the examination, * Over 50 years of age, * Non-smoker and non-alcoholic, * No psychiatric disorders affecting cognitive status and no medication affecting cognitive status, * Complete blood count was performed within the 6 months prior to the date of inclusion in the study, * No dental treatment within the last 1 year, * Periodontal examination was performed by expert periodontologists who calibrated the inter- and intra-examination, * Individuals diagnosed with periodontitis as a result of periodontal examination and radiographic examination, and * For individuals diagnosed with Alzheimer's disease: Recording their stage according to the Clinical Dementia Rating (CDR) and Standardized Mini-Mental Test (SMMT) scores Exclusion Criteria: * Individuals with fewer than 10 teeth, * Individuals with uncontrolled systemic disease, * Individuals who regularly use anti-inflammatories or corticosteroids

Locations (3)

Bolu Abant Izzet Baysal University

Bolu, Turkey (Türkiye)

Bezmialem Vakif University

Istanbul, Turkey (Türkiye)

Uskudar University

Istanbul, Turkey (Türkiye)

Outcomes

Primary Outcomes

Probing pocket depth

Measurement of the depth of a sulcus or periodontal pocket determined by measuring distance from a gingival margin to the base of the sulcus or pocket with a calibrated periodontal probe.

Time frame: Baseline

Bleeding on probing (BOP)

The number obtained by dividing the sum of the positive areas by the sum of the examined areas is multiplied by 100 and the value obtained is expressed as the percentage of bleeding at probing (BOP%).

Time frame: Baseline

Periodontal inflammatory surface area (PISA)

It is the calculation of the area of ulcerated periodontal pockets showing bleeding on probing based on the periodontal epithelial surface area.

Time frame: Baseline

Secondary Outcomes

Clinical attachment level

Clinical attachment level (CAL) is a more reliable indicator of periodontal support around a tooth than probing depth alone, as it is measured from a fixed anatomical landmark-the cementoenamel junction (CEJ)-which remains constant over time. Calculating CAL requires two measurements: the distance from the gingival margin to the CEJ and the probing depth. In cases of gingival recession, CAL is calculated by adding the probing depth to the distance from the gingival margin to the CEJ. In cases of gingival overgrowth, CAL is determined by subtracting the distance from the gingival margin to the CEJ from the probing depth.

Time frame: Baseline

Plaque percentage

The presence or absence of plaque is determinant, recorded as (+) in the presence of plaque or (-) in the absence of plaque, and the percentage of the entire mouth affected by plaque is expressed as a percentage (P%).

Time frame: Baseline

Data from ClinicalTrials.gov

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Stage I: mild Alzheimer's disease, Stage II: moderate Alzheimer's disease, Stage III: severe Alzheimer's disease

Standardized Mini-Mental TestDIAGNOSTIC_TEST

Cognitive status is assessed with the Standardized Mini-Mental Test.

Recording the number of teeth present

Time frame: Baseline

White blood cell count

White blood cell (WBC) count measures the total number of leukocytes in peripheral blood, usually expressed as cells per microliter (cells/µL). WBC is essential for evaluating immune status, infections, and inflammatory conditions.